Match ends, AFC Wimbledon 1, West Ham United 3.
West Ham survived a scare at League One AFC Wimbledon as they came from behind to reach the Carabao Cup third round and secure Manuel Pellegrini's first win as manager.
Joe Pigott headed the hosts ahead from Mitchell Pinnock's corner.
Wimbledon's Rod McDonald was sent off after 18 minutes but West Ham had to wait until the second half to equalise.
Issa Diop made it 1-1 before Angelo Ogbonna scored the visitors' second, with Javier Hernandez sealing the win.
Wimbledon produced a gutsy defensive performance to frustrate the Premier League visitors, who made nine changes to the side that started last weekend's 3-1 defeat at Arsenal.
Ukraine forward Andriy Yarmolenko, signed from Borussia Dortmund, and Spanish forward Lucas Perez, brought in from Arsenal, made their first starts.
Yet the Hammers, bottom of the Premier League table after three straight defeats, were behind after just 72 seconds as Pigott, who played in non-league for Maidstone last season, found the net with a superb header.
McDonald was dismissed after two bookings in the space of five minutes for fouls on Robert Snodgrass and Hernandez.
West Ham were not able to capitalise on the extra man advantage until midway through the second half when Diop fired home from outside the penalty area, the French defender's first goal since joining the club from Toulouse for a club record £22m in June.
The Hammers took the lead for the first time with seven minutes remaining: Ogbonna with a header from Snodgrass' corner.
Hernandez scored the third in added time after taking the ball round keeper Tom King.
'I was worried'
West Ham boss Manuel Pellegrini: "I was worried because you play against these teams that defend really well and then you are losing 1-0 in the first minutes, after working the whole week not to suffer those kinds of goals.
"The best thing the team did tonight was that we kept calm - we continued moving and creating space.
"It's important to win. If we lose this game, that's another consequence - it's very important. We need to continue working and I hope on Saturday we can have our first victory in the Premier League."
AFC Wimbledon boss Neal Ardley on the red card: "At the time I was stunned. The first yellow is fair enough as he misses the ball. The second, I think he has gone down very easy. In our league that happens all over the pitch and it's not given.
"It's a massive decision. We can't cause them problems after that and it was going to be attack against defence. It's a game changer."
- 26McDonaldBooked at 18mins
- 11PinnockSubstituted forWordsworthat 68'minutes
- 18HansonSubstituted forAppiahat 79'minutes
- 39PigottSubstituted forNightingaleat 26'minutes
- 14ObiangBooked at 11minsSubstituted forFelipe Andersonat 45'minutes
- 20YarmolenkoSubstituted forMasuakuat 90'minutes
- 27PérezSubstituted forAntonioat 81'minutes
- 8Felipe Anderson
- Tim Robinson
- Shots on Target
Second Half ends, AFC Wimbledon 1, West Ham United 3.
Goal! AFC Wimbledon 1, West Ham United 3. Chicharito (West Ham United) left footed shot from the left side of the box to the centre of the goal. Assisted by Arthur Masuaku.
Substitution, West Ham United. Arthur Masuaku replaces Andriy Yarmolenko.
Corner, West Ham United. Conceded by Toby Sibbick.
Offside, AFC Wimbledon. Anthony Wordsworth tries a through ball, but Kwesi Appiah is caught offside.
Foul by Michail Antonio (West Ham United).
Liam Trotter (AFC Wimbledon) wins a free kick in the defensive half.
Attempt missed. Andriy Yarmolenko (West Ham United) left footed shot from the centre of the box misses to the left. Assisted by Michail Antonio.
Attempt missed. Aaron Cresswell (West Ham United) left footed shot from outside the box is too high. Assisted by Declan Rice.
Attempt saved. Michail Antonio (West Ham United) right footed shot from outside the box is saved in the centre of the goal.
Goal! AFC Wimbledon 1, West Ham United 2. Angelo Ogbonna (West Ham United) left footed shot from very close range to the bottom left corner. Assisted by Robert Snodgrass with a cross following a corner.
Corner, West Ham United. Conceded by Adedeji Oshilaja.
Attempt blocked. Robert Snodgrass (West Ham United) right footed shot from the right side of the box is blocked. Assisted by Andriy Yarmolenko.
Substitution, West Ham United. Michail Antonio replaces Lucas Pérez.
Offside, West Ham United. Andriy Yarmolenko tries a through ball, but Pablo Zabaleta is caught offside.
Substitution, AFC Wimbledon. Kwesi Appiah replaces James Hanson.
Corner, West Ham United. Conceded by Scott Wagstaff.
Attempt blocked. Felipe Anderson (West Ham United) right footed shot from outside the box is blocked. Assisted by Declan Rice.
Pablo Zabaleta (West Ham United) wins a free kick in the defensive half.