How the Hawk-Eye instant-replay system has changed tennis

Monday August 26th, 2013

Andy Murray reacts to a Hawk-Eye review at Wimbledon in 2013. The system has been in place since '06.
Julian Finney/Getty Images

In its everlasting quest for relevance in professional sports, tennis fights a losing battle. It simply can't compare to the NFL, NBA or Major League Baseball in terms of television ratings or daily conversation.

There is one category, however, in which tennis unquestionably rules: instant replay.

The Hawk-Eye system, now in its eighth season at the tour level, represents the height of efficiency. For all the talk about advanced technology and the desire to "get it right" when an official's call comes under question, only tennis moves beyond a snail's pace.

Surely you've thrilled to the sight of NFL referees disappearing into a hooded area -- described by Bleacher Report's Dan Levy as "a cross between a voting booth and a plate camera from the 1850s" -- to review a call. Baseball umpires trot off the field and down into a hallway, while NBA referees gather around a courtside TV set. The delays are interminable, there's no guarantee of a satisfactory result and the fans have no idea what's taking place.

Hawk-Eye not only dismantles a tennis controversy in a matter of seconds, but spectators get to watch replays right along with the players. It's fun, lightning-quick and decisive, absolutely clearing the air for the ensuing point. Some controversy exists, but only as it regards the "challenge" stipulations or the merits of a raging temper tantrum.

Occasionally, you'll hear a dreamy reminiscence about the tempestuous 1970s, when the unbridled petulance of John McEnroe, Jimmy Connors and Ilie Nastase became an essential (if distasteful) ingredient to tennis' popularity. Whether it made for uproarious fun or an outright disgrace, people paid attention and younger players took notice, spawning future generations of hot-headed complainers.

Still, the game had to grow up. McEnroe certainly did, evolving into one of the most entertaining and insightful tennis analysts, and he was among the first to defend Hawk-Eye, telling reporters, "This is great. I hate to be in the position of defending umpires, but not having to worry about calls is a pretty big thing for us. I wish we'd had this when I was playing. I would have saved a lot of energy."

For those who have followed the careers of Serena Williams, Caroline Wozniacki, Jerzy Janowicz or the now-retired Andy Roddick, just to name a few, it's clear that Hawk-Eye did not eliminate the noisy tennis argument. An angry player will find an avenue to vent, one way or another. But the disputed line call has mercifully vanished on the "show" courts of major events and anywhere else Hawk-Eye is in play. As James Blake put it so well, "I don't need to go to bed now wondering if that serve was really in or out. I looked up. It was in."

Fittingly, Hawk-Eye was the creation of a 26-year-old British mathematician/computer expert named Paul Hawkins in 2001 (what if his last name had been Merglefurp?). It employs several high-speed cameras that surround an area, tracking visual data into a computer that reproduces the ball's path and pinpoints its landing spot, with a margin of error of 3.6 millimeters.

It was first used that year in cricket, initially met with great resistance but soon accepted for its accuracy and immediacy. Tennis followed suit in 2002 for the benefit of television analysts, and it became evident that such crystal-clear evidence shed essential new light on controversial calls. Two years later came the boiling point: a quarterfinal match between Williams and Jennifer Capriati at the 2004 U.S. Open.

At deuce on Capriati's serve in the first game of the third set, Williams drilled a clear winner with her down-the-line backhand; television replays showed it undeniably inside the line, and the line judge called it in. Inexplicably, chair umpire Mariana Alves overruled the call -- and Williams couldn't contain her frustration. Veritably stalking the chair, wagging her finger and shouting "No, no, no," she wasn't hearing of it. "That was my point," she said through the din of the crowd. "What are you talking about? That was not out."

Capriati went on to win the match 2-6, 6-4, 6-4. Afterward -- and it's crucial to remember that at this stage of her career, Serena had been tolerant of dubious officiating -- Williams, who was victimized by other terrible calls in the third set, said, "Listen, I'm never one to argue, but this one ... I'm very angry and bitter right now. Yes, I'm extremely angry. And bitter. I feel cheated. Should I keep going?"

There was no need to elaborate. In a statement released an hour after the match, tournament referee Brian Earley acknowledged Alves' mistake, indicated that she would not officiate another match in that tournament and said officials were looking into the possibility of using instant-replay technology for disputed points.

The process was now in motion. After a test run in September 2005 at the Hopman Cup in Perth, Australia, Hawk-Eye made its official tour debut with an eight-camera system on March 23, 2006, in what was then called the NASDAQ-100 (both men and women) in Miami. By way of approval, then-ATP chairman Etienne de Villiers declared in a conference call, "To me, it was always crazy that with modern GPS technology, we can tell where a person is to within a yard or meter on planet earth, and yet we can't tell whether a tennis ball is in or out."

Jamea Jackson, at the time an up-and-coming American player, was the first to challenge a call -- and she proved to be wrong. Later in that match, Ashley Harkleroad became the first to lodge a successful challenge. In all, 161 calls were challenged during that event, and 53 were overturned.

Such technology would always be out of the question at the French Open, where marks leave a clear imprint on clay, but in the wake of Hawk-Eye's success in Miami, the other three majors signed up: the 2006 U.S. Open and the 2007 Australian Open and Wimbledon. In the words of former tour standout Cliff Drysdale, "[Hawk-Eye] allows [players] to get on with what a tennis match should have always been about: an athletic competition and not an argument about which player is getting hooked."

Initially, there were no set rules as to the challenge system. Some events allowed players two per set, others stipulated unlimited challenges. In March 2008, the International Tennis Federation collaborated with the men's and women's tours to declare a uniform standard: three unsuccessful challenges per set, plus an additional challenge in a tiebreaker. Any time a player was proved correct, he or she would retain that challenge.

"In my 20 years in professional tennis," an enthusiastic Andre Agassi said, "this is one of the most exciting things to happen for players, fans and television viewers."

The initial stages of Hawk-Eye technology revealed some inconsistency. During a match at the 2007 U.S. Open, one replay showed that a ball had touched the line but declared that it was out. At Indian Wells in 2009, a replay picked up the second bounce instead of the first. Disturbing, yes, but nothing compared to the confrontational campaign staged by perhaps the greatest player of all time, Roger Federer.

Federer depised the new technology from the beginning, saying, "I don't see the point of it" and dismissing it as "nonsense." At Wimbledon in 2007, he pleaded with the chair umpire to disregard a Hawk-Eye replay -- showing a Rafael Nadal shot just barely in -- because he was convinced it was out. He subsequently asked (unsuccessfully) for the system to be turned off, saying it was "killing" him.

At the 2008 U.S. Open, with male players averaging a 30 percent success rate on challenges, Federer went a dismal 5-for-28 (17.9 percent), often appearing to challenge out of spite.

"That's just his utter dislike of the system," Drysdale said at the time, according to Forbes. "He's one of the few players out there that hates it, and I think sometimes he calls a challenge even when he knows he won't get the call. He's old-school."

Federer's attitude grew even more cantankerous at the 2009 Australian Open, when the Hawk-Eye system failed to produce a result on a crucial line call. The penalized player turned out to be his opponent, Tomas Berdych, but that didn't sway Federer's opinion after the match.

"What do I think about [Hawk-Eye]? It's horrible," he said.

The ensuing years mellowed Federer's stance, but not entirely.

"What I like without Hawk-Eye is just the players challenging the umpires more often," he told reporters at last year's Dubai event. "The umpires had to be very aware. People today don't lose energy over arguing with umpires any more, which back in the day we used to. I think also their mental strength came into play more often. Now you just move from point to point to point, so you don't see that much character. That's kind of what I miss.

"I believe it's pretty accurate. So I see fans liking that, but then those are maybe the ones who don't remember the arguments, back in the day with the umpires, which was when the booing started, fans getting behind you or against you. Those were the good days, too, sometimes. I mean, you can still do it, but for what reason?"

Challenge-related incidents became a major factor at this year's Wimbledon. In the first set of her quarterfinal against Agnieszka Radwanska, Li Na served an apparent ace on set point at 5-4, but it was called out and she failed to use a challenge -- one of three she had at her disposal. Radwanska wound up rallying to win that set and the match.

Midway through the fourth set of his epic semifinal against Djokovic, Juan Martin del Potro saw the score go to 5-all, instead of deuce, because he didn't use his last available challenge (his shot was called out and it stood, while TV replays showed it had gone in). In the final against Andy Murray, Djokovic found himself out of challenges at 5-all in the second set.

That's what really irritates analyst Mary Carillo: the notion that such wondrous technology cannot be used at a crucial time.

"I don't like the idea of challenges in the first place," she said. "Players having to decide when to make a call? That's insane. You're on the run 80 feet away and you have to decide if it could cost you the set. Early in a set, you might waste three ridiculous, vanity challenges, and guess what? Bad judgment, and you're out of challenges at crunch time."

From a chair umpire's point of view, consider this comment to historian Steve Flink by Sweden's long-respected Lars Graff, who called the 2009 men's final at Wimbledon: "It's great that a player can challenge a call at match point down, and if he wins that challenge, the match goes on. It also has great entertainment for the crowd. I worry, though, that because of Hawk-Eye, some umpires don't take as much action as they should. If you make an overrule and the overrule is wrong ,you can lose your confidence and become afraid to make decisions. I find it easier, because even if I make a mistake, the players won't worry about it since I've built up credibility with them."

Through all the debates and discussion, credibility is at the heart of Hawk-Eye's impact on tennis, a sport that values its time-honored traditions but is constantly moving forward. As much as instant replay addressed the complications of on-court arguments, it was also a reaction to the dramatic improvements in racket and string technology.

For years, in the era of wooden rackets, the game moved at a certain pace. Line judges and chair umpires didn't find it terribly difficult to determine a close call, and the players saw even the most distant shots with reasonable clarity. Once the oversized metal rackets came into play, beginning in the mid-1970s and taking firm hold in the '80s, players began hitting the ball harder than ever before. They abandoned the traditional natural-gut strings in favor of polyester and other synthetic brands, creating a much bigger "sweet spot" and infinitely more power.

"You can't even begin to describe the difference between the wood-racket era and what followed," former player and current TV analyst Brad Gilbert said. "People are crushing the ball so hard, it's almost like a different sport, just teeing off from the baseline and really changing how the game is played. The serve-and-volley days are just about over -- the ball's coming so fast from the other side of the net, it usually doesn't make sense to rush up there and get passed."

Bypassing the magic of technology doesn't make much sense, either. Instant replay is here to stay in tennis, viewed with great envy by sports mired embarrassingly in the past.

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