Leeds United mocked last season's infamous Derby 'Spygate' scandal ahead of their first game following promotion to the Premier League.
Marcelo Bielsa hit the headlines in 2018-19 for sending a member of his Leeds staff to Derby's Moor Farm training ground to report on their training routine.
The 64-year-old manager publicly admitted to spying on the Rams and a number of other Championship clubs in a bid to gain an extra edge over the opposition.
His actions created friction between the two clubs, and tensions threatened to boil over following their clash in the playoff semi-finals.
Derby won the two-legged contest 4-3 on aggregate, and Frank Lampard's players proceeded to mock Leeds supporters by making binocular gestures while celebrating on the Elland Road pitch.
The Whites bounced have back from that disappointment to storm clear at the top of the table in their latest campaign, with their return to the top-flight now assured after West Brom's 2-1 defeat at Huddersfield on Friday.
Bielsa's men were named champions when Brentford lost at Stoke a day later, and preparations will soon begin for the club's first appearance in the Premier League since 2003-04.
Leeds' penultimate game of the season is taking place at Pride Park on Sunday, with Derby now guaranteed to finish outside of the top six under the stewardship of Phillip Cocu.
The newly-promoted Whites couldn't resist aiming a dig at the Rams just before kick-off, as they published a video via social media of the stadium being viewed through binoculars.
Derby players lined up to give Leeds a guard of honour before the contest, and Charlton will follow the same protocols when they travel to Elland Road on the final day of the season.
Wild scenes of celebrations took place outside the ground when their promotion was confirmed last week, with injured midfielder Kalvin Phillips stepping out to address supporters by the main reception.
The 24-year-old paid tribute to Bielsa for guiding Leeds back to the promised land, stating: "We’re ecstatic. Promotion means everything. There’s no manager I’d rather be under than Marcelo Bielsa.
"He’s the best in the world.”
Reporters were also able to catch Bielsa outside his home in Wetherby, and he was seen thanking and shoulder bumping fans while also posing for a few photos.