David De Gea has warned Manchester United that they need to be much more switched on against West Ham to avoid a repeat of last season's 3-1 defeat to the Hammers.
The Red Devils, who were managed by Jose Mourinho at the time, were comfortably beaten by Manuel Pellegrini's side - a result that meant they'd suffered their worst start to a league campaign in 29 years.
And De Gea is aware of the threats posted by the Londoners heading into Sunday's latest Premier League meeting, urging his team-mates to be ready to go from the off.
"I believe they have a decent side with some good players who are important to them," the Spaniard told the club's official website. "They are on the up at the moment, but we still have bad memories from last season, so we have to be much more switched on right from the off than we were then.
"There are three very important points at stake for us to remain up there near the top, and also for the younger lads to keep gaining in confidence. We also want to show that’s what we’re here for, going away to difficult grounds and going there for the three points.
De Gea also saluted the role that the United supporters play in helping lift the team, adding: "They are vitally important to us. Our fans that follow us away from home are just incredible.
"Sometimes it’s just like we are playing at home in those away fixtures! It’s amazing. It helps us all tremendously down there on the pitch, we can always feel the warmth from our fans and that is hugely important to us."
The Spain international could face compatriot Pablo Fornals at the London Stadium and he expects that the former Villarreal star still will be a big player for West Ham, despite him having only made one Premier League start so far this season.
"I know him from the national team, we’ve been called up together in the same squad once or twice. He’s a quality player and I think he can contribute very well for West Ham. He really showed what he could do at Villarreal and he has a lot of talent and he’s a top player."
West Ham centre-back Issa Diop played in the 3-1 win over the Red Devils last season and he is urged his team-mates to put in a similar performance, insisting that with the quality in their squad they can beat anyone on their day.
"We played a very good game against them last season. It was our first win at home last season, and a very good moment for us," he told the Hammers' official club website.
"Sunday’s going to be a different game, so we have to try to do the same thing as last year. We have to play our football and not think about Manchester United.
"We have a very good team and can beat anyone, so we are confident. In the Premier League every game is difficult, but we are ready for this game. I think if we play our football, we’re a team who can do anything."