LONDON (AFP) - Arsenal produced a scintillating start to overwhelm in-form Manchester United 3-0 in the Premier League on Sunday and give embattled manager Arsene Wenger something to smile about.
Wenger was pilloried in the British press after Tuesday's 3-2 home defeat by Olympiakos left his side struggling to avoid a group-stage exit in the Champions League, but five days on he presided over a win that equalled his best league result against United.
Alexis Sanchez was the hosts' inspiration, scoring with a neat back-heel and an 18-yard howitzer inside the first 19 minutes to take his tally to six goals in three games after last weekend's hat-trick at Leicester City and a midweek header against Olympiakos.
Mesut Ozil joined in the early onslaught, netting from Theo Walcott's seventh-minute cut-back, as Arsenal secured a win that took them up to second place, two points below leaders Manchester City.
United were seeking a fourth consecutive league win, which would have seen them return to the summit, but instead Louis van Gaal's met with a defeat that saw them slip below Arsenal on goal difference.
It was United's first loss at the Emirates Stadium since May 2011 and the manner of defeat raised questions about the durability of their title credentials, just as Arsenal were strengthening theirs.
Michael Carrick was one of two changes made by Van Gaal, the other seeing Ashley Young come in at left-back, and the decision to pair Carrick with his fellow thirty-something Bastian Schweinsteiger was quickly made to look suspect as Arsenal ran riot almost from kick-off.
The first goal arrived in the sixth minute, with Aaron Ramsey sliding a pass down the inside-right channel for Ozil, whose cross was brilliantly and inventively back-heeled home at the near post by Sanchez.
Barely a minute later it was 2-0 as Walcott found space behind Matteo Darmian on the Arsenal left and pulled the ball back for Ozil to slot a first-time shot past a statuesque David de Gea.
United had not had time to draw breath and soon Sanchez had added a third, gathering a pass from Walcott, stepping inside three defenders and slamming a thunderbolt into the top-right corner from 18 yards.
It was the first time United had conceded three goals in the first 20 minutes of a Premier League match.
With Wayne Rooney's first touch betraying him, Memphis Depay running down blind alleys and Anthony Martial non-existent, United were not threatening a response and Arsenal could have extended their lead before half-time.
Santi Cazorla and Walcott shot wide, while Sanchez picked out Ramsey stealing into the box with a fine lofted pass from the left, only for the Welshman to miscue his volley and send the ball looping wide.
A chance finally fell the visitors' way a minute before the interval, but after neatly gathering Darmian's cross, Martial could only drill his shot against the legs of recalled Arsenal goalkeeper Petr Cech.
Van Gaal made two changes at half-time, introducing Antonio Valencia for Darmian and Marouane Fellaini for Depay, and farming the disappointing Rooney out to the left flank.
With three central midfielders on the pitch, United became a lot less porous, even if the decision to keep Morgan Schneiderlin on the bench was puzzling.
Belatedly, they began to make inroads, Cech repelling long-range efforts from Young and Rooney and then bravely diving to save at the feet of Schweinsteiger.
But Arsenal squandered opportunities of their own, with Ozil and substitute Olivier Giroud spurning presentable chances by sweeping low shots straight at De Gea.
A chastening afternoon for United was summed up when Rooney ballooned a shot well clear of the bar in the closing stages, prompting howls of derision from Arsenal's gleeful fans.