Substitutes Lucas Perez and Felipe Anderson raised hopes of a comeback, but they were extinguished when Toby Sibbick struck the fourth two minutes from time.

Boss Pellegrini pulled no punches afterwards. He said: "Was I angry at half-time? Yes of course. I was ashamed of them.

"I didn't expect it, the attitude, playing against a team that sits two divisions below us, but in football, you can lose in two or three balls.

"They started the way we needed to start and when you have such high pace with the quality of the players and we didn't have the same level."

Marko Arnautovic was left out of the squad following his recent flirtation with a move to China.

Yet 10 minutes after the final whistle West Ham announced the Austrian forward had signed a new contract, although they made no mention of the length of the extension.

Pellegrini, not at all impressed by the whole Arnautovic saga this month, refused to even discuss the announcement, angrily insisting: "I only talk about the cup.

"Ask me about the game today and I will answer. Any other question I will not answer."

By contrast, it was a sweet evening for Dons boss Wally Downes, a fully paid-up member of the original Wimbledon 'Crazy Gang' from back in the day, as well as a former West Ham coach.

"It was terrific, I'm really pleased for the boys, they put in a shift, said Downes, whose side only four days earlier were beaten 3-0 at home by Fleetwood.

He added: "Of course, you don't expect to be 3-0 up against a Premier League team.

"I said you don't get medals at half-time in any game, it was important we approached the second half well. We proved that by getting the third goal, it was terrific.

"The first time they've not performed for me was Tuesday night. Having to play this game the fear factor kicked in.

"If they'd played as badly it would have been a cricket score. The attitude was spot on tonight."

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