The home side came from behind with goals from against relegation-threatened Scunthorpe, which leaves the Londoners seven points off the top six.
Motor Racing supremo Bernie Ecclestone chose to sit in the stands at Loftus Road instead of sunning himself in Australia for the opening race of the Formula One season.
And the 77-year-old co-owner of the West London club must have wished he was in Melbourne instead of a wet South Africa Road Stand when Grant McCann fired League One-bound Scunthorpe ahead after just seven minutes.
Former Southampton defender Fitz Hall brought down Geoff Horsfield on the edge of the area and McCann stepped up to curl his left-footed shot round the wall and into the bottom left-hand corner leaving keeper Lee Camp unsighted.
For all of QPR's attractive passing football in the middle of the park it was their finishing in the final third which was denying them a chance to level the score.
Joe Murphy produced a world-class save to keep out Agyemang on 23 minutes.
Hungarian Akos Buzsaky played an inch-perfect cross from the right to the big centre-forward, but he failed to connect cleanly with the shot and the Iron stopper saved brilliantly.
Minutes later Buzsaky picked up the ball on the halfway line and played in defender Damien Delaney via Vine, but he pulled his shot agonisingly wide of the far post.
But five minutes before the break QPR were gifted a way back into the game when referee Mike Thorpe awarded them a soft penalty.
Scunthorpe defender Izzy Iriekpen was adjudged to have brought down Vine and skipper Martin Rowlands coolly slotted home the spot-kick.
Rangers continued to dominate possession in the second half but without any creating any real chances.
Mikele Leigertwood should have given the West Londoners the lead on 71 minutes but he fired wide from 12 yards.
Buzsaky continued to torment the Iron defence but failed to deliver the decisive ball when it mattered.
For all of QPR's possession, the winner finally came in the 78th minute when Buzsaky split the Scunthorpe defence for Agyemang to fire home for his ninth goal since his move from Preston.
Vine then coolly lobbed Murphy in the final minute to make sure of the points.
The result leaves Scunthorpe needing a miracle to stay in the Championship and QPR clinging on to dreams of Premier League football next season.