Five things we learned in Barclays Premier League action Saturday:
Yet Arsenal won 2-1. The victory was even more unlikely than last week's five-goal fightback against Tottenham because the statistics don't entirely lie. On Saturday, except after Robin van Persie had put the Gunners ahead in the 92nd minute, Liverpool dominated. In the first half the home team was imperious, repeatedly carving through the Arsenal defense. But it could not turn chances into goals.
Before Saturday, Liverpool was unbeaten at Anfield in the league, but it had drawn eight of its 12 home games and scored just 14 goals. Some of that is bad luck. Liverpool has hit the woodwork more than any other team. But it is also wasteful. Dirk Kuyt squandered a penalty and also hit the post. Luis Suarez, lively and dangerous without end product again, also hit a post. Wojciech Szczesny, the Arsenal goalie, saved impressively from Kuyt, following up the penalty, and Suarez. Liverpool's best second-half chance fell to Martin Kelly, a fullback who finished like a defender. His air shot from three yards was ugly. It's perhaps not entirely surprising that the goal that gave Liverpool the lead was stuck into the net by Laurent Koscielny, an Arsenal player.
Arsenal doesn't need to worry about turning chances into goals, provided those chances fall to Van Persie. His first goal, before halftime, was a neat enough header. What was so impressive was the absolute certainty with which the Dutchman finished. The winning goal was beautiful. When Alex Song lobbed the ball forward, Van Persie outwitted the Liverpool offside trap and lost Jamie Carragher. He still had time to set himself perfectly to meet a ball dropping over his shoulder and invent a volley of elegant economy, accuracy and power. With the game on the line, he again showed complete certainty.
"I don't think we deserved it to be honest," a grinning Van Persie told Sky.
He was being too modest. The winner was his 31st goal of the season and his 25th in the league.
Liverpool has managed just 30 goals in 27 games. However pretty the football, that's an ugly number.
That reaction of the referee and the Liverpool players, and fans, who applauded him off, was in marked contrast to their behavior when Arteta went down in the first half. Then, as a poor Arsenal clearance drifted harmlessly into the Liverpool half, Arteta collapsed holding his leg. The fans booed. Halsey did nothing. As Arsenal players urged Liverpool to kick the ball out, the home team played on.
In both cases the reactions were appropriate. Referees have instructions to stop play if there's a suspicion of a head injury. In any other circumstances, it's up to the players. The convention of kicking the ball out of play when an opponent is merely winded is a fairly recent development. It's terribly sporting. It also smacks of self-interest: "I stop when you have cramp, you stop when I do." No one plays through pain. It's a habit that can be exploited by the cynical, and modern professional soccer can be a deeply cynical game. Players and fans know it.
At Wigan later in the afternoon, where Swansea was defending a 2-0 lead with 10 men, Ashley Williams of Swansea and Mohamed Diamé of Wigan both received yellow cards following a scuffle which began when home players felt the visitors were faking injuries.
At Anfield, the Liverpool fans made clear with their loud booing that they thought Arteta was trying to gain his team time after it had given away possession. They might well have been right. As the attack developed, Arteta hopped up and limped back into action.
On Saturday, City beat Bolton 2-0 to again pull five points clear of its only rival for the league title. The victory was also City's 19th straight at home in the league. That equals the Premier League record, set, of course, by United.
For City, it was a relatively close-run thing. Goalie Joe Hart even had to make a couple of spectacular saves, and Ryo Miyaichi and David Ngog hit the bar. On the other hand, if Mario Balotelli, in particular, had been more efficient, City could have been three up in the first 5 minutes.
"Maybe he was up too late," Roberto Mancini, the City manager, said of the striker who stayed out all Thursday night. Balotelli did score in the second half as City won an entertaining game comfortably.
Did we learn anything new from a match that had the same outcome as the previous 18 league games at the Ettihad? Not really. City proved again that they are both good and consistent. But so are United. The one home game City probably needs to win is against United at the end of April.
As if to prove it, the performance of the Chelsea team that Villas Boas sent out at West Bromwich on Saturday was a ghost of past displays. Chelsea had beaten West Brom 15 straight times in the league. On Saturday, it was bullied throughout. The only surprise was that the home team only won 1-0 and took 82 minutes to score. Gareth McAuley striking from close range after one of a series of desperate scrambles in the Chelsea area.
It could have been different. Daniel Sturridge, again showing why he isn't getting his wish to play as a central striker, wasted two excellent chances. The miss that will haunt Villas Boas, Chelsea and Lampard came in the dying second, when the midfielder has so often saved his team in past. Lampard ghosted into the area, timing his run perfectly to reach the ball five yards out and unmarked. He shot wide.
Chelsea has won only one of its last seven. It is now three points behind surging Arsenal in the race for the fourth Champions League place. For Villas Boas, this is getting scary.
The PGMOL used one of the performance measurement programs increasingly popular with top clubs to study games from the referee's perspective. It released its findings earlier this week. The headline numbers are that Premier League soccer has become 20 percent faster in the last five years, which is a statistic for another day, that assistant referees (or linesmen) get 99.3 percent of decisions right and that referees get 93.3 percent of decisions right. That sounds pretty good. It's an A+ average. Soccer people were impressed. They should not have been.
The study also claimed, rather hyperbolically, that referees have to make a decision every 12 seconds. Let's pretend we believe this. It works out at five decisions a minute or some 450 a match (assuming that the referees get the amount of added time right and it cancels out stoppages in play). So, 6.7 percent of 450 equals about 30 wrong decisions in every match. That's actually a lot of errors.
Of course not all decisions are of equal weight. And often, whether a decision was wrong depends on which team you support. Sky, which aired the Liverpool-Arsenal game, displayed the broadcaster's obsession with penalties and referees, by showing the incident in which Szczesny brought down Suarez, repeatedly. Was Halsey right to award the penalty? The conclusion: none of the studio experts could decide.
So, 93.3 percent refereeing accuracy might not be as impressive stat as it seems. One thing that can be said is that referees make fewer mistakes than most players and pundits.