Leeds boss Marcelo Bielsa admitted to sending members of his backroom staff to secretly gather information on Lampard's Derby team - only for one of his employees to be caught outside the Rams' training ground.
Leeds went down to 10 men though in the 78th minute after Gaetano Berardi was dismissed after a second yellow card for a late lunge on Bradley Johnson.
Leeds won the last top flight title before the advent of the Premier League in 1992, but suffered a financial implosion around the turn of the century and fell from its perch toward the top of the English game.
Leeds beat Derby 1-0 in the first leg, and took the lead thanks to Stuart Dallas' goal midway through the first half Wednesday. And the Leeds fans chanted at Lampard about 'spygate'.
And in addition to the Derby players taking an opportunity to snipe back at the Leeds fans as they celebrated in front of the away supporters mimicking looking through a pair of binoculars similar to Mateusz Klich's celebration back in January, so did the club's official Twitter account.
In the 58th minute, Derby's Harry Wilson converted a penalty kick after teammate Mason Bennett was brought down in the box by Leeds defender Liam Cooper. I've heard a lot of people saying I'm crying about Spygate.
Before the two-legged tie with Derby, he had said he would not speculate on his future: "I would never say that if we stayed in the Championship I won't stay here, otherwise you say the importance of this club is linked to the division in which it plays". "I thought we were still in the game then but I'll admit that goal came at just the right moment". Dallas scored again to equalise but Marriott scored his second to take Derby through.