Derby produced a brilliant display at Elland Road to come from two goals down on aggregate to progress 4-3.
Jack Marriott’s second-half brace turned the tie on its head for the Rams, after Stuart Dallas gave the hosts an early lead.
Mason Mount and Harry Wilson added to the scoring, while Leeds saw Gaetano Berardi sent off for two yellow cards.
The two sides have history together after the infamous ‘Spygate’ scandal, in which Leeds boss Marcelo Bielsa organised for members of his coaching staff to hide outside Derby’s training ground and make notes.
After Leeds’ sly tactics were caught out, Lampard reported the case to the EFL, and United fans have not let him forget it.
After Saturday’s 1-0 win for Leeds in the play-off semi-final first leg, the visitors mocked the Rams boss by creating a chant to the tune of a famous Oasis song that ends: “Stop crying Frank Lampard.”
But after last night’s win, Lampard got the last laugh and was filmed singing along to the song jokingly in the dressing room.
Injured star Duane Holmes filmed the clip and posted it to Twitter, and it was fair to say Rams fans were loving it.
Derby’s official Twitter page also posted a video of the song, which showed the whole squad getting involved while champagne was sprayed around the dressing room.
One fan responded with a song of his own, tweeting: “You cheated at home, you cheated away, you were top of the league but you threw it away, stop crying Bielsa.”
Another replied: “Absolutely love it. Love Frank and Jody, and all our boys.”
Lampard was asked about the Spygate scandal after the game, and insisted that he hadn’t let it enter his mind before the game.
Asked if the result meant more because of the history between the two teams, he told Sky Sports: “Maybe, maybe. I’m not going to lie, maybe it is.
“I heard a lot of people saying that we were crying about Spygate but I haven’t thought about Spygate for a long time.
“We played them, we prepared, and we got a result.”
Derby will now go on to face Aston Villa at Wembley for a chance to win promotion to the Premier League.
For Lampard, the game will have an added personal element to it as he prepares to go up against friend and former Chelsea team-mate John Terry – one of Villa’s assistant managers – on the touchline.