Early in the first half West Ham had a goal chalked off by the officials.
Felipe Anderson was deemed to be beyond the last defender when he volleyed in, though replays showed Manchester United defender Diogo Dalot had in fact played him onside.
And at half time, former Hammers boss Slaven Bilic was disappointed with the decision.
“The goal is completely good, this should be 1-0 to West Ham,” Bilic said on BT Sport.
“Then you say it’s difficult for the [assistant] referee to see the right foot of Dalot.”
Manchester United took the lead later in the first half through a Paul Pogba penalty.
Robert Snodgrass was adjudged by referee Graham Scott to have fouled Juan Mata just inside the 18-yard area, but former Premier League referee Peter Walton says it was the wrong call.
“I think that what’s happened there, as the ball has come through, and we’ll see it now, the referee has got a great view of the incident, no one’s in the way of him there,” Walton said.
“He feels there Snodgrass has come through the back of Mata and bundle him over.
“And quite confidently he has awarded the penalty kick.
“We can see his view here and yes it looks like he’s smashed straight through the back of him.
“But if you look at it from the side angle here, it’s just a shoulder to shoulder.
“Snodgrass has shown a bit more aggression in looking to win the ball and Mata has gone over.
“And unfortunately, in my opinion, I don’t think that is a penalty kick.”
But when asked if VAR would have ruled the penalty out if in use, Walton said: “No I don’t, it’s a subjective call you see, so VAR wouldn’t have intervened.”
