Nico Terol took advantage of a mistake by 125cc title leader Marc Marquez to take a comfortable victory in Sunday's Indianapolis Grand Prix - and move to within nine points of the world championship lead.
Terol may prove to be closer, or even leading the championship, depending on the outcome of an investigation into Marquez cutting the track.
Marquez had stormed from pole to a 2.6sec lead over Terol by lap 9 of 23, when he was bucked from the seat of his Ajo Red Bull Derbi.
The Spaniard put up a brave fight to stay on but, having dislocated his shoulder last time out in Brno, such a save was difficult and he duly dropped off at low speed.
The 17-year-old then sprung to his feet and remounted, but had dropped to 14th by the end of the lap, while Terol was handed a seven-second lead over Aspar Aprilia team-mate Bradley Smith.
Smith then crashed out of second place after losing the rear on lap 13, while under pressure from Sandro Cortese and Pol Espargaro.
Terol, the early title leader who missed a round after back injuries in Catalunya, went on to take his third victory of the season - and second in a row - by 4.995sec over Marquez's Ajo team-mate Cortese with Espargaro in third for Tuenti Derbi.
Marquez, a five time 2010 winner, carved his way up to fifth by the finish, passing several riders on the very last lap, but he also cut some corners after running wide and is now under investigation by Race Direction.
As the result presently stands, the top three riders in the championship - Marquez, Terol and Espargaro - are covered by ten points heading into next weekend's Misano round.
UPDATE: Marquez was demoted to tenth for cutting the track. He now leads the championship by just four points from Terol and five from Espargaro.
Revised race results - Indianapolis:
1. Terol (Aprilia) 23 laps
2. Cortese (Derbi) +4.995s
3. Espargaro (Derbi) +10.856s
4. Vazquez (Derbi) +15.402s
5. Rabat (Aprilia) +19.912s
6. Webb (Aprilia) +20.093s
7. Krummenacher (Aprilia) +20.702s
8. Moncayo (Aprilia) +26.797s
9. Folger (Aprilia) +27.666s
10. Marquez (Derbi) +39.840s
Smith (Aprilia) DNF