LONDON — Alexis Sanchez produced a stunning second-half hat trick in 15 minutes as Arsenal cruised to a 5-1 victory over struggling West Ham on Saturday in the Premier League.

Sanchez's hat trick, along with goals from Mesut Ozil and Alex Oxlade-Chamberlain, ensured Arsene Wenger's side kept in touch with league leaders Chelsea.

Saturday's haul saw Sanchez tie Diego Costa as the top scorer in the league with 11 goals this season. Sanchez has thrived since switching from the left wing to centre forward at the beginning of the campaign.

"He has all the ingredients to be a top-class striker and showed that again today," Wenger said. "He's quick, he can dribble, has a short back-lift and a killer instinct."

For Wenger, it was "a strong team performance with very few weak periods - the only regret was that we didn't take our chances in the first half."

A fifth straight league match without victory will increase the pressure on West Ham manager Slaven Bilic, but his side's lack of intensity against a London rival appeared to annoy him even more than the result.

"Somewhere along the line we lost intensity in training, we have to bring that back, without that we can't rely on quality," the former Croatia manager said.

"We were humiliated - I want to say sorry to the fans and everybody who has anything to do with West Ham United, because it was really bad."

The visitors were afforded too much space in the final third from the outset at the London Stadium, with West Ham not helped by James Collins' muscle injury forcing the introduction of Alvaro Arbeloa after just seven minutes.

Arsenal wasted a handful of opportunities in the opening stages, before the ever-reliable duo of Sanchez and Ozil produced decisive contributions.

Chile forward Sanchez raced through before squaring for Ozil to tap home in the 24th.

Arsenal was never taken out of its comfort zone before Sanchez produced a moment of magic to double the lead in the 72nd.

The striker received the ball outside the box on the left with little danger apparent before spinning Arthur Masuaku, skipping away from Angelo Ogbonna and driving low past West Ham goalkeeper Darren Randolph into the bottom corner.

Sanchez's first strike triggered a spate of five goals in 15 minutes, as he beat the helpless Randolph once more with unerring accuracy as the ball fell to him on the edge of the box in the 80th.

Just three minutes later Andy Carroll grabbed a consolation on his return from injury before Oxlade-Chamberlain got in on the act, curling the ball in from outside the box for 4-1.

Sanchez had the final word as he completed his hat trick with a sublime dummy and dinked finish to move Arsenal up to second in the Premier League, three points behind Chelsea.