A visibly delighted Arsene Wenger praised hattrick hero Alexis Sanchez or his ‘killer instinct’ after his treble routed West Ham United 5-1 at their new home the London Stadium.

Arsenal were always in control as Mesut Ozil struck on 25 minutes to break the deadlock after an assist by the impressive Sanchez.

The Gunners eased into a 3-0 lead before substitute Andy Carroll pulled one back with fewer than 10 minutes remaining – briefly raising fears of a grandstand finish to match the entertaining 3-3 draw at Upton Park last term.

But Alex Oxlade-Chamberlain hit the North Londoners fourth, followed up moments later by the red- hot Chilean grabbing his third and Arsenal’s fifth to make it 5-1.

Wenger said afterwards to a packed press conference: “Alexis Sanchez has a killer instinct.

“He has all the ingredients to be a top class striker. He is quick to close down. He can dribble. He has good movement. He is sharp.

“The only regret was that we didn’t take our chances in the first half – but overall we were strong. We gave a strong team performance for 90 minutes.

“We were always dangerous and maintained the pressure in the final third - we were pacy and patient and that made the difference. “

Discussing his Latin forward he added: “He has again shown that South Americans are the leading strikers in the world. The top strikers in Europe all from South America now – you have to acknowledge that.”

Sanchez who has now hit 13 goals for the club in 18 starting appearances this term appears to be enjoying his new role as centre forward, including his memorable hattrick against the Irons.

The Frenchman explained: “He likes playing in that position. When it comes off and you walk away with the ball under your arm it’s a good feeling and it will give him a taste for more – but he has the qualities to play there.”

By netting five goals in the annihilation of West Ham Arsenal became the leading scorers in the Premier League with 33, including topping the goalscoring charts with 18 goals struck away from home.

He concluded: “We kept the ball well. It was a strong team performance today. We score more goals away from home than at home.

“Do we play with a bit more freedom away from home? It will be interesting to analyse that.

“If we look at our performances away from home we have been very convincing.”

However, Wenger showed sympathy for his counterpart Slaven Bilic. He said: “We had lots of confidence. And West Ham had less confidence than last year.

“West Ham have a handicap of a new ground and they are not completely comfortable – especially if it’s added with a lack of confidence.”

A deflated but dignified Bilic said afterwards: “Arsenal humiliated us.”

There was a minor scare when Wenger admitted Sanchez had a small problem with his back at half time, but Wenger shrugged it off saying: “He actually looked stronger in the second half than in the first.”