Teenage striker Marcus Rashford continued the dream start to his Manchester United career, scoring two goals and setting up another in a 3-2 win over title-chasing Arsenal in the Premier League on Sunday.

Only playing because of United's chronic injury crisis, the 18-year-old Rashford marked his league debut by scoring in the 29th and 32nd minutes to put his team 2-0 ahead, three days after a double in the Europa League against FC Midtjylland on his senior United debut.

After former United striker Danny Welbeck replied for Arsenal, Rashford set up Ander Herrera for a shot from the edge of the area that deflected in off Laurent Koscielny.

Mesut Ozil made it 3-2 in the 69th but fifth-place United held on comfortably to move three points off the top four. Arsenal, which put in an off-colour performance against a young and injury-hit United side, dropped five points behind leader Leicester. The North London side hasn't won in the league at Old Trafford since 2006.

United manager Louis van Gaal, under much pressure amid the team's troubles this season, delivered some light relief when he fell to the ground theatrically while remonstrating with the fourth official in the technical area. The Old Trafford crowd roared with laughter, adding to an atmosphere that was buoyant throughout the game as United's youngsters proved too energetic for Arsenal.

Rashford must think professional soccer is easy. In his first two games as a pro, both of them high-profile ones, in the space of three days, the striker has scored as many goals as Radamel Falcao did in a whole year for United last season.

"I could imagine the first game he did that because he is a striker coming in to score goals and the first match is always good," Van Gaal said. "The second match he has to do what the manager is willing him to do, and he did it fantastically."

'The timing and intelligence of his movement was great. He could be a very positive surprise for Man United.' - Arsenal manager Arsene Wenger on Man United's Marcus Rashford

Arsenal manager Arsene Wenger was also impressed with Rashford, who hadn't started a game above under-19 level before Thursday.

"The timing and intelligence of his movement was great," Wenger said. "He could be a very positive surprise for Man United."

He is showing no fear on the biggest stage and demonstrated to Van Gaal that the Dutchman has had a goal poacher at his disposal all along during the team's rough patch this season. Injured pair Wayne Rooney and Anthony Martial are among the strikers unavailable to Van Gaal at present.

Rashford was given a standing ovation by United fans when he was substituted after 80 minutes.

For his first goal, the young striker was lurking 12 metres out as Gabriel failed to adequately clear Guillermo Varela's cross. A first-time shot was too pacey for Arsenal goalkeeper Petr Cech as Rashford became United's third-youngest Premier League scorer.

Three minutes later, Rashford was celebrating again after heading home a clipped right-wing cross from Jesse Lingard from just outside the six-yard box. Arsenal manager Arsene Wenger, who said Friday that he hadn't heard of Rashford, threw up his hands in disgust.

Arsenal was flat, strangely, and its passing lacked the usual crispness. But the team managed to reduce the deficit before halftime when Welbeck got behind marker Morgan Schneiderlin at a free kick and headed in Ozil's cross.

Rashford wasn't finished. In the 65th, with Arsenal's defence backing off him in apparent panic, the teenager laid the ball off for the inrushing Herrera to shoot first time. The ball was heading for the far corner until it deflected off Koscielny's chest to wrong-foot Cech.

Ozil replied four minutes later, volleying in after David de Gea saved from Welbeck, but Arsenal didn't threaten De Gea in the final 20 minutes.