Wayne Rooney scored a hat-trick that included two free-kicks as Manchester United beat Arsenal 8-2 to top the Premier League on goal difference.

Ashley Young also scored a brace as the Red Devils ran riot at Old Trafford.

Danny Welbeck gave United the lead in the 22nd minute, looping a header over Wojciech Szczesny in the Arsenal goal, before having to go off with a hamstring injury.

Gunners striker Robin van Persie then saw his penalty saved by David de Gea after Theo Walcott was brought down by Jonny Evans.

Young made the visitors pay six minutes later, curling an effort into the far corner from outside the area.

It was three before half-time when Rooney bent a free-kick over the wall and into the top corner.

Arsenal pulled a goal back in first-half injury-time when Walcott fired through de Gea's legs.

After the interval, Rooney sent Szcezny the wrong way with his second free-kick of the match, before setting up the fifth.

His pass went through Laurent Koscielny's legs to Nani, who chipped the ball over the keeper.

Substiute Park Ji-Sung made it six before van Persie scored Arsenal's second.

Arsenal have now had a player sent off in each Premier League game this season after Carl Jenkinson received a second yellow for a challenge on substitute Javier Hernandez.

Rooney completed his hat-trick from the spot after Walcott was adjudged to have brought down Evra.

It was eight when Young scored a similar effort to his first in stoppage-time.

United lead the table after three games, while Arsenal sit just above the relegation zone, in 17th.