After falling from the lead at the last two races, Jorge Lorenzo kept his Fiat Yamaha on two-wheels while Dani Pedrosa and Valentino Ross crashed around him to win Sunday's Indianapolis Grand Prix.
Pedrosa, whose total domination of the Indy weekend was narrowly broken by Alex de Angelis in morning warm-up, had bolted from pole and was sitting a few tenths clear of Rossi and Lorenzo when the front of his Repsol Honda folded on entry to the tight final turn at the end of lap 4 of 28. The Spaniard remounted a distant 17th and last.
Pedrosa's downfall gave Rossi and Lorenzo a five-second lead over Colin Edwards, but title leader Rossi was next to fall when he suddenly slammed shoulder-first into the asphalt on entry to turn two on lap 10 - just one lap after losing the lead to Lorenzo.
A stunned Rossi rejoined in 16th, but was struggling with bike damage and retired shortly after being overtaken by Pedrosa on lap 13.
Rossi had looked to be slightly off-line just before his front-end fall and, after returning to the pit, Rossi immediately began examining the telemetry for clues to his accident. The exit marked Rossi's first DNF of the year and only the second time he has failed to score points from the twelve rounds held so far.
Lorenzo, who began the race 50 points behind Rossi and openly talking of settling for second, cruised to his third victory of the season by 9.435sec - which he celebrated with a huge wheelie, before climbing the trackside fencing 'Indy 500' style and being given a Captain America shield to go with his special helmet design.
The 22-year-old has now halved Rossi advantage to 25 points (one race win) with five rounds and 125 points still undecided.
The mistakes by Pedrosa and Rossi handed second place to de Angelis, who had drafted past Edwards for third on lap 6 - but soon had another American, Nicky Hayden, in close pursuit.
de Angelis, currently jobless for 2010, had never taken a MotoGP podium while Hayden was on target for his first rostrum as a Ducati rider.
The Sammarinese was ultimately able to shake-off Hayden and claim Honda Gresini's second podium of the season, while Hayden found himself under intense pressure from Andrea Dovizioso - the man who replaced him at Repsol Honda - during the closing stages.