Arsenal 1 Manchester United 2
Valencia and Welbeck keep up the pressure on City
Manchester United kept within touching distance of the top of the Barclays Premier League thanks to Danny Welbeck's late winner at Arsenal.
United knew they needed a win to keep close to leaders Manchester City and they looked on course for victory when Antonio Valencia nodded home Ryan Giggs' cross.
Arsenal rallied in the second half and pulled one back through Robin van Persie, but their hopes of a point were dashed nine minutes from the end when Welbeck steered Valencia's cross home from close range.
The game was not a patch on City's 3-2 win over Tottenham in terms of entertainment and quality, but Sir Alex Ferguson will be happy to have ground out another win which further proves he still has the know-how to formulate a title challenging team at the grand old age of 70.
In reality, though, Arsenal made their task much easier thanks to an abject first-half defensive display from the Gunners' makeshift back four.
Despite the thrilling nature of the encounter between Tottenham and City earlier, Arsenal v Manchester United has proved to be a humdinger of a game in Premier League history.
Pizza-throwing tunnel clashes, touchline spats and on-field rucks have taken place in recent encounters and today's match had even more added spice as the Gunners were out for revenge after their 8-2 humiliation at Old Trafford.
Both managers had predicted a cagey encounter on this occasion, however, and the first 10 minutes suggested they were right to do so.
Jonny Evans cleared an Alex Oxlade-Chamberlain cross and Anders Lindegaard easily gathered a shot from Aaron Ramsey.
Theo Walcott embarrassed Phil Jones with his quick feet, causing the defender to trip up and hit the deck and he had to come off for Rafael after just 15 minutes.
Per Mertesacker and Johan Djourou cleared dangerous United crosses and Valencia just failed to tap home a flick-on.
Oxlade-Chamberlain bamboozled Patrice Evra to sneak in to the United box and laid off to Walcott, but he blazed over from 18 yards.
Evra then easily beat Alex Song down the left and crossed for Nani but Szczesny saved.
Giggs played Wayne Rooney into the box and the striker went down after appearing to have his arm pulled by Song but Mike Dean waved play on.
The ability of United's wingers to skip past makeshift full-backs Vermaelen and Djourou was a particular source of frustration for the home support.
Nani easily beat the Swiss and whistled a sharp ball across the box.
n the opening minute of first half injury time Giggs was given space down the left flank and he floated a cross over to the back post where Valencia beat Vermaelen in the air to nod home.
Arsenal went off at half-time to a chorus of boos and Wenger, clearly unimpressed by Djourou's contribution, replaced the defender with 18-year-old Nico Yennaris who was making his league debut.
Van Persie was presented with an easy chance five minutes after the break when Tomas Rosicky pinched the ball off Chris Smalling and squared for him but he fired wide from 10 yards with the goal gaping.
Van Persie then tricked his way past three United defenders and squared for Rosicky but his drive was blocked by Evra.
Laurent Koscielny burst in to the United half and laid the ball off to Oxlade-Chamberlain but his drive flew barely an inch wide.
Welbeck raced through after a headed clearance from the United back line and slipped the ball past the advancing Szczesny only to see his goal-bound effort cleared off the line by Per Mertesacker.
Tribute: Robin van Persie had a message for his grandfather after scoring
The striker fell in the challenge from Arsenal's goalkeeper, but despite United's protestations, Dean did not pull play back for a penalty.
Then with 20 minutes to go, Arsenal stunned the visitors with an equaliser.
The Gunners broke through Oxlade-Chamberlain who squared for Van Persie and his reverse shot flew through Evans' legs and in off the post.
Arsenal fans reacted with fury when Wenger brought Oxlade-Chamberlain off two minutes later for Andrey Arshavin.
Nani hobbled off and was replaced by Paul Scholes after being injured in a tackle and Ferguson sacrificed substitute Rafael for Park Ji-sung.
The Emirates Stadium was shocked in to near silence with nine minutes left after Welbeck put the Red Devils ahead.
Valencia lost his marker Arshavin and played a clever one-two with Park before squaring to Welbeck, who bundled home from close range.
Van Persie flung himself towards a header in injury time but United cleared and Evans calmly guided Mertesacker's header in to Lindegaard's arms soon after as the visitors clung on for a vital win.
Man City 3 - 2 Tottenham
Mario Balotelli's injury-time penalty gave Premier League leaders Manchester City a vital victory after Tottenham's stirring comeback looked set to earn them a point at The Etihad.
Balotelli calmly slotted home the decisive penalty to give City the points
City set the platform for a win early in the second half with two quick goals from Samir Nasri and Joleon Lescott - but Spurs delivered a devastating response as an opportunist goal from Jermain Defoe and a magnificent strike from Gareth Bale drew them level in a burst of four goals in nine minutes.
Balotelli emerged from the bench and into the chaos that seems to be his constant companion - picking up a booking for a foul on Benoit Assou-Ekotto then escaping punishment after appearing to stamp on Scott Parker, an incident which went undetected by referee Howard Webb.
Defoe was then inches away from putting Spurs back in front in stoppage time before Italian Balotelli was inevitably the central figure in the final twist that ensured Roberto Mancini's side maintained the gap ahead of their pursuers at the top of the table.
Spurs' backroom staff were enraged by Balotelli's clash with Parker and their burning sense of injustice would have been made even more acute when he calmly strode forward to score from the spot with only seconds remaining after he had been hauled down by Ledley King.
The visitors clearly felt he should not even have been on the pitch, adding to their frustration after they had demonstrated considerable character and resilience to fight their way back into the game.
City boss Mancini will have had mixed emotions - delight at a crucial three points but also anxiety at the manner in which his side allowed Spurs back into the game.
Defoe, as expected, was Redknapp's selection in attack ahead of Emmanuel Adebayor, who was unable to figure against City, his parent club, during his season-long loan period.
In a first half that was fiercely contested, the only striker who got the chance to shine was City's Sergio Aguero as Spurs outnumbered City in midfield and contained the league leaders in relative comfort.
The Argentine saw his goalbound shot inadvertently blocked by Edin Dzeko, then demonstrated great strength and awareness to hold off Younes Kaboul and find David Silva, who dragged his shot just wide.
Aguero was frustrated by Spurs goalkeeper Brad Friedel after Richards forced his way into area - but there was still no indication of the torrent of goals that were to hit The Etihad after the break.
The first came after 56 minutes when Silva, with trademark creation, threaded a pass through for Nasri to thump a finish past Friedel. And when Lescott bundled home Dzeko's flick from a Nasri corner three minutes later, City could see daylight.
Not for long, however, as Spurs were back in business within seconds as the hour approached. Stefan Savic failed miserably in his attempt to deal with a clearance, heading straight to Defoe, who accepted the gift with relish as he rounded City keeper Joe Hart to score.
City's fans had gone from elation to anxiety, but Dzeko should have eased their concerns when he was played in by Silva. The Bosnian never looked convincing as he lashed his effort way over the top.
Bale showed no such uncertainty when he put Spurs level in spectacular style after 65 minutes. He took Luka Modric's pass and clipped a finish that possessed pace, power and precision high into the top corner beyond Hart, who had no chance.
City had introduced Balotelli for Dzeko, but his first meaningful contribution was to pick up a yellow card from referee Webb for a foul on Assou-Ekotto.
The coming together with Parker that provided a major talking point followed soon after, before a thrilling second half received the climax it deserved.
Defoe could not stretch far enough to turn Bale's cross into an open goal - leaving the stage clear for the turbulent Balotelli to write another chapter into his eventful Manchester City story.
Source: BBC Sport