Wayne Rooney became the all-time top scorer against Arsenal in the Premier League era by netting Manchester United's second in a smash-and-grab 2-1 victory at the Emirates Stadium.

United's only shot on target was Rooney's sealer in the 85th minute, after a Kieran Gibbs own goal gave them a fortuitous lead.

Olivier Giroud, on his earlier-than-expected return to action, scored a 95th-minute reply, but it was too little, too late for the Gunners.

Hosts Arsenal were dominant in the opening half an hour as their pressure high up the pitch forced United's makeshift back four into several errors.

It was a careless clearance from United keeper David de Gea that gifted the home side their clearest sight of goal just before the quarter-hour mark.

Jack Wilshere surged through on goal, but somehow shot straight at De Gea instead of rolling it past him or squaring it to the unmarked Alexis Sanchez to tap home.

United's defensive worries worsened moments later when left-back Luke Shaw had to come off with an injury after rolling his ankle in a challenge with England teammate Alex Oxlade-Chamberlain.

Oxlade-Chamberlain then had a chance of his own after beating the offside trap. He tried to round De Gea, but the Spanish keeper did not commit and followed the winger out wide before making the stop.

On the half-hour mark, Wilshere was extremely lucky not to be sent off when he appeared to headbutt Marouane Fellaini after a challenge between the pair. Referee Mike Dean spoke to both players and decided that a talking to was all that was required.

United ended the half better than they had started it, with Angel Di Maria and Chris Smalling both going close.

De Gea's fine form continued in the second half as he denied former United striker Danny Welbeck and Sanchez in the opening moments, before United silenced the bulk of the Emirates with a fortuitous goal.

Arsenal goalkeeper Wojciech Szczesny and defender Gibbs clattered into each other when trying to clear a cross, and the ball fell to Antonio Valencia, whose swipe goalwards ricocheted off Gibbs, still on the floor, and spun into the corner of the net.

The goal came moments after Wilshere seemed to suffer a serious injury and Szczesny was also forced off for the knock that he sustained in the clash with Gibbs.

Twice more De Gea denied the Gunners in the 63rd and 68th minutes, first holding onto a powerful low header from Sanchez, before Santi Cazorla's fierce volley was also well-held by the United stopper.

Giroud was brought on for his first appearance since recovering from a long-term injury and he almost scored an equaliser, but could not keep his header down from a corner.

Rooney put the game to bed five minutes from time by collecting a pass from Angel Di Maria on the counter-attack and clipping the ball over Szczesny. It was his 11th goal against the Gunners in the league, moving him one clear of Robbie Fowler's 10.

The visitors could have made it three in added time, but Di Maria fluffed his lines on the break when trying to emulate Rooney's chip, with Arsenal committed to grabbing a goal.

Eight minutes of injury time were signalled and Giroud fired into the top corner in the fifth of those to give Arsenal feint hope of a late comeback.

They could not grab an equaliser, though, and United held on for a first away win under Louis van Gaal which moves them up into the top four.

Defeat for Arsene Wenger's side leaves them eighth in the table and a whopping 15 points behind league leaders Chelsea.