Del Potro, Murray among players to watch at Madrid Masters

Juan Martin del Potro: I saw him lose to Fernando Verdasco in the San Jose tournament earlier this year, and that player barely resembled the one who dismantled Verdasco, 6-2, 6-2, in Sunday's Estoril final. He had another impressive win over Robin Soderling, in decidedly damp conditions, although he admitted that humidity -- always a factor at this time of the year -- is not a favored climate for his rehabilitated right wrist.

In trying to find perspective on his comeback, Del Potro endearingly referred to "heart" getting him through the difficult times and allowing him to reach at least the semifinals in five of his past six events. He certainly has the willingness to fight through discomfort, and if you've come across a louder, more punishing forehand anywhere on tour recently, report to headquarters immediately.

Del Potro would face Nadal (and let's hope that happens) in the third round.

Andy Murray: That elbow injury sounded serious, but he claims to be "feeling great" after being forced to withdraw from the Barcelona Open. The last we saw of him, he gave Nadal a spirited battle (sore elbow and all) before going down in three sets in Monte Carlo. And there's no question, in light of his many discouraging losses this year, that he has a point to prove.

"I don't care what people say, I know I can win a major," he said this week. "I'm sure that I'll get there."

Just as long as we don't hear much more from Murray's former coach, Pato Alvarez, who went way over the top this week by claiming, "Murray's the best there is. He's a better player than Nadal and the other top guys. He's more explosive. He has a better backhand. He has a better serve."

Just guessing, but I'm not sure even Andy's mother, Judy, believes any of that.

Roger Federer: Analyzed to death, Federer is a bit exasperated over the doom-and-gloom forecasts, the latest arriving after he lost to Jurgen Melzer in Monte Carlo. We have reached the stage in which he and Nadal find themselves in the same half of the draw, so that's a potential semifinal to watch.

Robin Soderling: He hasn't reached his customary form at any point this year, and although he downplays injuries to his Achilles and knee, those have to be significant factors. If your 2011 image of Soderling is his surprising Australian Open loss to Alexandr Dolgopolov, be sorry the Ukranian bombed out early in Madrid with a 6-1, 7-5 loss to Santiago Giraldo. There would have been a rematch in the second round.

As the week goes on, much attention will be focused on Djokovic, whose upgraded physical endurance has been as impressive as (and responsible for) his 27-match winning streak. Last year at this time, he retired due to illness at what amounts to his own tournament (the Djokovic family owns and operates the Serbia Open), and then he pulled out of Madrid. This year, after taking a week off to rest a tender knee, Djokovic stormed through his hometown event and defeated Feliciano Lopez in straight sets for the title.

Reflecting back on the spring of 2010, Djokovic admitted having "some private issues that I was struggling with, and that affected my health and my game. I wasn't really enjoying playing tennis at that time." We see him now as more single-minded on the court, working with a sports psychologist and thriving on a gluten-free diet.

"My nutritionist has done a great job in changing my diet," he said in Belgrade. "It means I can't eat stuff like pizza, pasta and bread. I have lost some weight, but it's only helped me because my movement is much sharper now, and I feel great physically."

Meanwhile, behold the transition: As we speak, Nadal vs. Djokovic (not Federer) looms as the most exquisite matchup. "It breaks a bit of the usual duality," David Ferrer noted last week. "To have Djokovic there is a great moment. There will be bigger television audiences, and that's always good."

If it happens, note that Nadal is 9-0 against Djokovic in clay and 16-9 in their lifetime matches.

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Aranxta Sanchez Vicario caused a bit of a stir last week, telling a Spanish newspaper that today's WTA doesn't favorably compare to her era. "We had eight or 10 players who always had an extreme rivalry," she said. "Now everything is much more open. You can be number one without being a great champion. There is a lot more power in the game, but it lacks variety ... there were players with different games, stronger minds, more character."

The first instinct might be total agreement, if only to honor the memory of Steffi Graf, Martina Navratilova and Monica Seles. In terms of depth, though, Sanchez has it wrong, at least as it relates to her years as a top 10 player.

During the span of Sanchez Vicario's career, only one year, 1989, qualifies as legitimate evidence for her argument. As she rose through the ranks, stunning everyone with a win at the French Open, the tour was simply loaded: Graf, Navratilova, Seles, Gabriela Sabatini and Chris Evert (about to say farewell), with Jennifer Capriati only months from bursting onto the scene.

Take a close look, though, at the 1994-99 period -- the years in which Sanchez-Vicario finished in the top 10. Navratilova and Seles were past their prime (for vastly different reasons), combining for just one major title between them. The top 10 was quite the mixed bag, allowing room for Iva Majoli, Irina Spirlea, Tamarine Tansugarn, Anke Huber, Amanda Coetzer, Jana Novotna, Mary Pierce, Natalie Tauziat, Magdaleena Maleeva and Kimiko Date.

More variety? Yes, barely. More depth, in terms of "stronger minds" and "more character"? A dubious claim.

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NOTES: The Americans' cause had been left to John Isner, with Andy Roddick and Sam Querrey so quickly eliminated, but he couldn't keep it going Tuesday with a 5-7, 6-4, 7-6 (3) loss to Sergiy Stakhovsky ... Lots of talk about Brussels, the event preceding the French Open, on the women's side. Although most insiders doubt that either of the Williams sisters will be fit enough to play the French Open, it's conceivable that Serena, Venus and Kim Clijsters all could begin their comebacks in Belgium ... Good stuff from Li Na if she intends to resurrect top form this month: a first-round win over Maria Jose Martinez Sanchez, a masterful clay-court player who won last year's Italian Open ... Pete Bodo points out an interesting sidelight to the Donald Young-Patrick McEnroe affair, triggered last week by Young's profane reaction to being denied an automatic wild card into the French Open: During an 11-month period near the end of his playing career, McEnroe received wild-card berths into seven consecutive tournaments -- and never won a match. "I felt guilty taking them," McEnroe said. "Down deep, I knew I was just getting them because I was John's brother." ... And finally, this bit of perspective from Nadal, regarding his approach to the game: "When you compete, you go to die." Not sure anyone else has phrased it quite that way.