Slaven Bilic was disappointed with his team's performance after the Hammers fell to a 4-0 opening day defeat to Manchester United on Sunday.
West Ham's old nemesis, Romelu Lukaku, struck again with two more goals to add to his tally against the east Londoners, before late strikes from Anthony Martial and Paul Pogba added insult to injury.
Bilic spoke before the game of feeling optimistic for the trip to Old Trafford, so he was frustrated to see the visitors getting beaten at the basics and not giving themselves a chance of bettering last season's point against Jose Mourinho's men.
"I expected more, of course," the boss said. "I have to admit it, they were much the better side in every aspect of the game. They were better in the air, they were better on the floor and better in 50-50 challenges.
"We knew they had a strong side, but I expected us to do much better than we did on Sunday.
"We were much slower than them. They had pace up front and the quality, and we didn't want to get exposed in one-on-one situations, because in those situations, individually they can make a difference.
"So we wanted to create the situation that we are two against one in our favour, but to be fair we didn't have that today a lot.
"It's very hard to find positives when you lose 4-0, but we have to get up and get ready for the next game."
The goal which took the contest away from West Ham, Lukaku's second, soon after the restart, came from a wide set-play and Bilic was annoyed with the simplicity of the goal.
He added: "We knew that they have a threat on set-plays. They have four or five really tall players who are good in the box and that's why we practised set-pieces for three days in a row.
"We looked good, but if you give players like Lukaku so much time and are not close to them, you can't expect better than [what happened]."
The boss made a positive change when introducing Diafra Sakho from the bench not long after the hour, and he thought the Hammers created some positive situations, but admitted they need to show more focus if they are to make a swift improvement.
He explained: "We tried to switch to 4-4-2 because we needed another player up-front with Chicharito, who was quite decent but was isolated.
"So we put Sakho on with him and took a bit of a risk. We created some opportunities, some good situations which didn't end up with a shot or a good chance, but what we didn't want to happen was concede two goals late in the game.
"Basically we need to become more focused, because we have been training well. In the game we need to show determination in every situation, in every throw-in, because when you play Man Utd you need to beat them in that department.
"But they were better than us doing the dirty work and if they are better than you in the dirty work [they will win]."