Arsenal 1 - 2 Manchester Utd: Three points and a bruising as Danny Welbeck hits United’s winner

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 scored 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.

With fixtures against Liverpool, Chelsea and Tottenham on the horizon, United manager Sir Alex Ferguson was delighted to keep within three points of league leaders City, who beat title rivals Tottenham 3-2 earlier.

“We said before the game that winning after City had won their game was the important thing,” Ferguson said. “We did it in the right way, we played football and were adventurous and had belief in ourselves. I’m delighted with that at this time of the season.

“They are all important games, we have four massive away games and that is one out of the road.”

The game was not a patch on City’s win over Spurs in terms of entertainment and quality, but Ferguson will be happy to have ground out another win which further proves he still has, at the grand old age of 70, the know-how to formulate a title-challenging team.

In reality, though, Arsenal made United’s task much easier thanks to an abject first-half defensive display from the Gunners’ makeshift back four.

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, causing the defender to trip up and hit the deck and he had to go 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 referee 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.

In 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 made his league debut.

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.

Wenger reacted furiously to the Arsenal fans who criticised him for taking off Oxlade-Chamberlain. “I can understand that the fans are upset about the substitution, especially when it doesn’t work, but he [Oxlade-Chamberlain] had started to fatigue,” Wenger said.

“He was sick in the week. Arshavin is captain of the Russia national team.

“You have an 18-year-old kid making his first Premier League start and a player who’s captain of his country and they are querying the substitution? Let’s be serious.

“I’ve been a manager for 30 years and have made 50,000 subs. I do not have to justify every decision I make. I stand up for it.”

United’s win came at a cost, however. Jones was carried off on a stretcher after 15 minutes after turning his ankle, Nani hobbled off in the second half and left the stadium in a protective boot, while Rooney was also hobbling at the final whistle.

Ferguson, who was already without Rio Ferdinand, Anderson, Tom Cleverley, Ashley Young, Michael Owen and long-term absentees Darren Fletcher and Nemanja Vidic, said: “It’s not good news for us. I think Jones will be out for a few weeks – it’s ankle ligaments.

“Carrick was feeling his hamstring in the second half and he just had to sit in the middle of the pitch.”