Yet another Arnautovic free-kick is met firmly by a home head to clear. His deliveries so far from these set-pieces has been pretty dire.

The ref returns to Angelo Ogbonna and books him for a late foul on Mkhitaryan in the build-up to the Rashford shot.

So unlucky! Marcus Rashford unleashes an angled shot from outside the box that smashes into the base of the post and flies back out. He hit it beautifully. Deserved a goal.

Prawn Heed: Best and worst signings. Lukaku: big, strong, fast, scorer. Chicarito: not.

Ssxio: For the first time in a number of years, United look like United should do.

Javel Bleach: West Ham's quality is better than what they're showing: negative survival-mode.

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Simon Stone
BBC Sport at Old Trafford

Jose Mourinho is very smart this afternoon, with this suit and open-necked shirt look in his technical area.

And it looks like he has done some smart business in the transfer market this summer too.

Nemanja Matic was outstanding in the first-half and now £75m forward Romelu Lukaku has got himself two goals.

Victor Lindelof is the odd man out. The Swede is sat in the directors box having been left out of the United squad altogether today. He is not suffering from an injury, just overlooked.

Image source, Reuters

Lukaku should probably have a hat-trick. He is set up at the back post but his shot is pushed away by Joe Hart.

This after West Ham's first corner of the game is met by the head of the newly-introduced Sakho and just behind a couple of team-mates in acres of space.

Image source, Getty Images

Two changes for West Ham. Diafra Sakho and young Declan Rice come on for Edimilson Fernandes and Mark Noble. The latter does not look too thrilled to be subbed.

Oh, naughty. Antonio Valencia drags his studs down the heel of a West Ham man - Marko Arnautovic - in attempting to make a tackle. Valencia apologises but he still has to take a booking.

Ashic:Brace on debut? I'll have that, thanks. One more?

Paul L:Romelu Lukaku 2! Another neat finish, and Utd are looking like a team with a bit more intent this year...

T: As a West Ham fan I feel like it's the same not bothered tactics as last season. New signings same negative performance. Poor.

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Image source, PA

Maybe West Ham aren't done just yet. The ball is swung into the box and met by the head of Marko Arnautovic. His effort loops over the diving David de Gea and clips the bar.

3-0... no!

The flag is up to deny Manchester United a third as Rashford crosses for Mkhitaryan. It was the former who was off in collecting a pass from Juan Mata.

Image source, Reuters

John Murray
BBC football correspondent

He has got another one! Two goals from Romelu Lukaku on his Manchester United Premier League debut. What a start! And this time he celebrates in front of the East Stand. Romelu Lukaku is making his mark! He knew exactly what he was doing. This is becoming an excellent Premier League debut for his new club.

Image source, Reuters

Image source, Reuters

Cynical from Zabaleta. He plants his feet and allows Rashford to smash into him, halting a breakaway attack. Deserves the booking.

Robbie Savage
Ex-Leicester City & Wales midfielder on Radio 5 live

West Ham as an attacking threat have been very poor. You have got to feel sorry for Winston Reid and Mark Noble when they get on the ball because nothing is going on in front of them.

Image source, Reuters

Arnautovic has yet to hit one of his own men with a free-kick. He gets another chance to cross but plants it straight on to another home head.

Oh, poor finishing again from Manchester United. Paul Pogba shows strength and vision to hold off a man and then thread a pass for Marcus Rashford. It sets the young striker through on an angle, but his shot flies across goal and wide. Wasteful.

West Ham win an early free-kick wide right in the home half.

Arnautovic swings it in but Pogba heads clear near his own goal. No threat.

Seth: It was a dominant display of good quality football from Man Utd in the first half! Expect more of the same in second half.

Yullaw: Matic has been absolutely immense!

KN: Very slick one touch passing & playing at a faster pace than last season. Can we convert last season's draws into wins?

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Image source, Reuters

No changes. We are back under way.