Lukaku, a £90 million summer signing from Everton, has scored 11 goals in 11 games so far this season for United, but he was unable to add to that tally against Liverpool.

He was largely starved of chances, but a first-half miss, which resulted in a save by Liverpool keeper Simon Mignolet, was Lukaku's one moment in a frustrating game that finished 0-0.

But despite the miss, he has rejected suggestions that he can only deliver against lesser teams.

"Everything was going really fast," Lukaku said, when describing his missed chance against Liverpool. "I took the decision to put it there, but Simon made a good save.

"I don't think too much about it and will put the next one in the net.

"That [ability to overcome missed chances] has to be the striker's biggest strength -- knowing that you are going to score and that you are going to miss.

"But every time I miss, people put it like this. Lots of strikers in the league miss bigger chances than me and they score two goals -- but with me it's always 'Rom did this, Rom did that.'

"I don't know why. Maybe it's the standard people set. I accept that as a matter of fact. I'm always relaxed."

Lukaku's record at previous clubs against higher-ranked opponents was mixed, but he believes that his goal in United's UEFA Super Cup defeat against Real Madrid in August proved his ability to score against the best.

"I have heard that from people [that he doesn't score against big teams]," Lukaku added. "It's different when every time I played for Everton, we have a different mindset coming into the game.

"As a striker when I was over there, I had a good time. I learned my trade over there. I played there for four years. I am really grateful to the club no matter what happened.

"But sometimes it is difficult as well when you play against the top teams and you play not to win and don't really create chances. It is really difficult. Now I am in a team where we want to win against the big teams and we want to win every game, so I think the situation will change.

"I don't put pressure on myself, but I think the biggest pressure game for me was the Super Cup against Real Madrid. That was the game for me where everybody was looking at me and thinking will he do it there?

"I think it freed me from everything and I just kept going, tried to improve week in, week out.

"People will always say this and that, but my record in the Premier League is pretty good and I'm in a situation where the team is performing really well, but there is a lot of work to be done.

"I always say I try to be humble, look at the points I can improve and see how it goes."