Reigning 250cc world champion Marco Simoncelli won his fifth race of the season - two more than any other rider - in Sunday's Portuguese Grand Prix, which saw 2009 title leader Hiroshi Aoyama extend his advantage despite a fourth place finish.
Aoyama, who began the race just 13 points ahead of Alvaro Bautista, looked set to lose his title advantage when he dropped from first at turn one to eighth by lap three - while Bautista led the way.
But just two laps later the race, and perhaps championship, was turned on its head again when Bautista - having been squeezed back to a close fourth - was brutally thrown from his Aspar Aprilia after an apparent engine seizure just as he hit the brakes for turn six.
Subsequent mistakes by Raffaele de Rosa and Alex Debon helped promote Aoyama back up to fourth position, although the Scot Honda rider had already lost touch with race leaders Marco Simoncelli, Hector Barbera and Mike di Meglio.
The leading trio remained within one-second of each other until the midway point, when Simoncelli began to break noticeably clear. The Metis Gilera rider then extended his advantage to win by a lengthy 5.317sec.
The battle for second was much closer with di Meglio and Barbera still locked together as the last lap began - with Barbera then snatching second from the Frenchman into turn one.
Reigning 125cc world champion di Meglio, who had been just behind team-mate Bautista when he fell, saved his retaliation until the dash to the line, when he pulled alongside Barbera's Pepe World Aprilia to prompt a photo finish.
Barbera was initially credited with second by 0.001sec, but a subsequent review of the footage saw di Meglio given the position - with exactly the same race time - due to a faster race lap, resulting in plenty of podium confusion!
Meanwhile a visibly frustrated Aoyama confirmed fourth position by 2.3sec from Matteoni Aprilia's Jules Cluzel.
Simoncelli, who began the race 40 points from Aoyama, is now a threatening 28 points behind the Japanese with three races and 75 points remaining, while Bautista has dropped 26 points from the top.
Race results - Estoril:
1. Simoncelli (Gilera)
2. di Meglio (Aprilia) +5.317sec
3. Barbera (Aprilia) +5.217sec
4. H. Aoyama (Honda) +12.024sec
5. Cluzel (Aprilia) +14.349sec
6. Wilairot (Honda) +18.256sec
7. Luthi (Aprilia) +27.631sec
8. Pasini (Aprilia) +34.667sec
9. Debon (Aprilia) +45.410sec
10. Abraham (Aprilia) +45.891sec