West Ham manager Slaven Bilic said Tuesday's extra-time victory over Liverpool will "go into history" as one of the best games in the Hammers' history.
The FA Cup fourth-round replay appeared headed for penalties when Angelo Ogbonna scored his first goal for the club with a header in the 121st minute, putting West Ham through with a 2-1 win.
Last month, West Ham complete a rare double over Liverpool in the Premier League, and Bilic said adding the late dramatics of the cup tie will ensure Tuesday is a night long remembered.
"I know that we are through, but this is great, and it was for me a really great game of football," Bilic told BT Sport.
"It's like a classic FA Cup tie and it's going to go into history of West Ham's greatest games, no matter if it's only for the last-16. But against Liverpool, late-night kickoff, last season at Upton Park, great game, and a goal in the last minute.
"I think we deserved it, so I'm very proud of the guys. They left their hearts on the pitch."
The Hammers are, of course, leaving Upton Park at the end of the season but the famous old ground crackled with an atmosphere it will surely be impossible to recreate at the Olympic Stadium.
It was Dmitri Payet who floated in the free kick that Ogbonna headed in to send three sides of Upton Park into delirium. The Hammers are to offer French playmaker Payet a new contract just seven months after signing him, amid reports of a bid of £38 million from an unnamed Chinese club for him.
But Bilic added: "I'll say it again. We are a club moving forward and the most important moves are on the pitch. We must do everything we can to keep our best players, and he is our best player.
"He's happy here and very soon we will sort out his situation."
West Ham captain Mark Noble said he was already looking ahead to penalties, though he was relieved not to have taken one.
"You couldn't write it," Noble told BT Sport. "We had a similar situation last year that went to penalties and to be honest I'm out there thinking, 'Where am I going to stick my penalty?'
"And Angelo pops up and saves everyone the heartache of penalties, even their players. No-one likes to go out on penalties.
"Just for the fans tonight and the players' belief, we played well last week against Southampton and we didn't get nothing, but tonight we matched a very good team and we're into the next round."
Ogbonna joined Noble and was delighted by the timing of his first West Ham goal.
"I am very happy to score this goal in the last minute," he said. "I am really pleased for the supporters, for my team because everybody wants to go through so I am really happy."