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.

Javier Hernandez, who scored for Mexico at the 2018 World Cup, netted his first West Ham goal since 8 April

'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."