What can Chelsea learn from Man Utd defeat?
Manchester United's next two opponents will have watched Arsenal's victory over Sir Alex Ferguson's team with interest.
Schalke may have an almost impossible task when they face United on Wednesday in the second leg of their Champions League semi-final, although during this season we should learn to know better than to rule any team out.
Then Chelsea will travel to Old Trafford for a defining Premier League title battle four days later, with a renewed confidence after seeing signs that their opponents can be outwitted.
Many of United's problems this season, particularly away from home, have stemmed from their midfield, where an insistence on playing with two central midfielders has seen them concede possession.
Park Ji-Sung and United team-mates struggled to contain Arsenal's midfield
That was the case again against Arsenal, when Michael Carrick and Anderson were continually picked off by the Gunners central midfield trio of Alex Song, Jack Wilshere and goalscorer Aaron Ramsey.
Ferguson usually picks a midfield three to match Arsenal and opts to break on the counter attack, but this time was different as he asked Wayne Rooney to drop deep and track Song.
The reasons for that may have come from a recent success in playing Rooney behind Javier Hernandez, not least in the comfortable 2-0 victory over Schalke last Tuesday.
Yet without an extra body in midfield, and with the influential Ryan Giggs absent through illness, Song quickly found a way to join Arsenal's attack and at the same time neutralise Rooney.
In fact, such was Rooney's role that he did not make a touch in the Arsenal penalty box.
"I was surprised by how Manchester United set up," says former Arsenal defender and Match of the Day 2 pundit Lee Dixon. "I know Rooney can drop in and act as another midfielder but they really played a 4-4-1-1 and I think that was down to the personnel available.
"Although Rooney will drop back, he is not the best at wanting to and any Arsenal fan would have been happy to see him back there anyway.
"There were a couple of times when he was behind Carrick and Anderson in that holding role. I was thinking, what is he doing there? Basically, it was because they were short in that area.
"I'm pretty sure that, when it comes to facing Chelsea, Sir Alex Ferguson won't pick his side to play like that next week. They got overrun in midfield, but having said that, Arsenal didn't create too much."
In a hectic April, when United's big games came thick and fast, Giggs' impact was a common thread.
United's best two performances in recent weeks were away in the Champions League against Chelsea at the quarter-final stage and Schalke in the first leg of the semi-final, where the 37-year looked indefatigable.
Compare that with Sunday's defeat by Arsenal and the FA Cup semi-final loss to Manchester City two weeks ago where on both occasions the Welshman was missing.
Both defeats also came against sides who flooded the midfield and Chelsea boss Carlo Ancelotti may consider a similar policy in the game at Old Trafford next Sunday.
That will fit in with the Italian's orthodox 4-3-3 system but he might want to restore Didier Drogba as the central striker after the Ivorian played on the right of a front three against Tottenham on Saturday.
At times he cut a frustrated figure there despite a return to form in recent weeks, and Ancelotti will be mindful of his contribution in the Champions League quarter-final defeat at Old Trafford almost three weeks ago.
Drogba's influence in that game was obvious once he replaced the ineffective Fernando Torres at half-time. His 77th minute equaliser was only rendered meaningless by a lapse in concentration by his team-mates as United's Park Ji-Sung replied within a minute to put the tie out of reach.
Nicolas Anelka was also impressive in the first half at Old Trafford which leaves Ancelotti with a tantalising selection dilemma for the must-win game.
Although Drogba was peripheral on Saturday there were glimmers of the swagger returning to his game as he hit free-kicks from all sorts of range, hitting the bar with one of them from all of 35 yards.
That is backed up by statistics from his last six games where he has played more and contributed more compared to the previous six games after Torres' arrival at the club.
In that first run of six Premier League games where he played 303 minutes, he failed to score and assisted only one goal. He also only had five shots with a shooting accuracy of 20% and a pass completion of 55%.
The last half dozen games have seen an improvement where he has played 519 minutes, has scored twice and set up four goals. In addition, he has taken 28 shots with a shooting accuracy of 39% and a pass completion of 71%.
Drogba's growing confidence will be a boost to Ancelotti, and after admitting his error in leaving him out at Old Trafford, the manager has no reason not to go for broke.
"You presume that with Manchester United going for the title they won't be defensive at home but you just never know," Dixon adds. "Even though Ferguson will warn them, the players might just be a bit cautious. After all, a draw will do for them.
"I would imagine that Ferguson might even switch it round next week and put Dimitar Berbatov back in and leave out Hernandez.
"At home you would expect them to play differently but it is Ancelotti who has to take the bull by the horns and put United under pressure."