In what was a closely contested affair, up until that point it looked like Gary O'Neil's red card for a cynical challenge on Johnny Russell would be the moment that would define both side's promotion hopes.
Coming on the hour, the dismissal changed the shape of the game, as QPR dropped back and had to rely on several top saves from goalkeeper Rob Green to keep them in the game.
Wave after wave of Derby attack was repelled by a committed R's defence, but for many it was matter of when, not if the Rams would make the breakthrough.
Before that refereeing decision, the two sides had exchanged tentative blows with neither really seizing control, and as the match approached the 90th minute, it looked like extra time and perhaps penalties were on the agenda.
But up stepped Bobby Zamora, a 57th minute substitute, to pounce on a poorly defended Junior Hoillet cross that bounced in front of him inside the box, with the striker lashing the ball into the top corner past Lee Grant.
Remarkably, it was the very same left foot that scored the winner in the 2005 final as West Ham United beat Preston at the Millennium Stadium to seal promotion, but his goal today for London rivals QPR was a little more sweetly struck.
Zamora's strike was QPR's only shot on target compared to Derby's five, but it ensured Harry Redknapp took them back to the top flight at the first attempt, ensuring a £80 million windfall at the same time.