David De Gea hopes to celebrate his new contract in style by helping Manchester United make amends for last year's chastening loss at West Ham.
Months of speculation about the 28-year-old's future finally came to an end on Monday as the goalkeeper put pen to paper on a huge new deal until 2023 with the option of a further year.
Reduced to a watching brief in the midweek Europa League opener against Astana, De Gea will make his first appearance since signing that new contract in the capital on Sunday.
United head to West Ham looking to build on back-to-back wins, but last September 3-1 defeat at the London Stadium is still fresh in their minds.
"I believe they have a decent side with some good players who are important to them," De Gea said.
"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."
West Ham manager Manuel Pellegrini wants his team to show their ambition to compete with the top six when they take on United.
he Hammers went into the weekend eighth in the Premier League table but level on points with third-placed Tottenham after five matches.
In last season's meeting at the London Stadium, West Ham ran out 3-1 winners but Pellegrini expects a tough fixture this time.
The Chilean said: "We know that we have a very strong team in front of us, now we have a good test against United and we will try to beat them.
"It's the only way to try to arrive in the first six positions of the table, demonstrating every game that you are able to do it."
On the possibility of finishing in the European positions, Pellegrini said: "At this moment, when you have played just five games and you have eight points, you have the same points as Arsenal, as Manchester United, Tottenham, Chelsea, so we are demonstrating that.
"But you must extend those five games for the complete season. [If] you are able to do it in five, why are you not able to do it in 38?
"That's why I think we must not start any future game thinking that 'oh we beat Manchester United last season, now we are in a good moment' – we must demonstrate again because football changes in two or three days."
United have lost just once in this season's Premier League, to Crystal Palace at home, while the Hammers have had mixed form at the London Stadium.
They lost 5-0 to Manchester City on the opening day of the season but beat Norwich 2-0 in their last home game and Pellegrini wants to build on that result.
"We are going to try from the beginning, from the first minute of the game," he said. "They continue to be a big team, good players, with players that make a difference, so we must be very concentrated in our defending.
"Every game or every points that you don't lose at home is better for you. You see the statistics for all the teams, the most amount of points you have are at home.
"We are doing well playing away, but we need to be a strong team playing in our stadium."
In Sunday's other matches, Crystal Palace take on Wolverhampton Wanderers – still without a Premier League win this season – at Selhurst Park, while Arsenal face Aston Villa at the Emirates Stadium.
