Mika Kallio has snatched an unexpected British 250GP victory over Marco Simoncelli and Alvaro Bautista after the race leaders ran wide with one lap to go.
Simoncelli stole the early advantage, with pole sitter Bautista - whom Simoncelli beat on the last lap at Catalunya - taking several laps to work his way up to second.
Bautista briefly took the lead, but Simoncelli responded and the top two looked content to wait for another last lap showdown.
But world championship leader Kallio had other plans and - despite starting just 14th on the grid - had caught the top two with five of the 27 laps to go.
The prompted Bautista to retake the lead and the Mapfre Aprilia rider pushed hard to stretch away. But it didn't work and Simoncelli was close enough to try an inside pass heading into the final turn on the penultimate lap.
The move pushed both riders wide, allowing Kallio to sail effortlessly into a lead he held by 0.353secs over Simoncelli at the chequered flag. An unhappy Bautista took third and later had words with Simoncelli in parc ferme.
Kallio, who began the race just three points ahead of Simoncelli, is now eight points in front of the Italian heading to Assen next weekend.
Race results - Donington Park:
1. Kallio (KTM)
2. Simoncelli (Gilera) +0.353secs
3. Bautista (Aprilia) +1.237secs
4. Barbera (Aprilia) +8.875secs
5. Luthi (Aprilia) +11.359secs
6. Aoyama (KTM) +16.124secs
7. Debon (Aprilia) +16.136secs
8. Simon (KTM) +18.007secs
9. Takahashi (Honda) +33.271secs
10. Espargaro (Aprilia) +49.681secs
Laverty (Aprilia) DNF