Scott Dixon blew the IndyCar Series title race back open with his victory in the first race of this weekend's double-header on Houston's Reliant Park street circuit.
The Ganassi driver spent the opening phase of the race stalking early leader Will Power, and claimed the advantage when the Australian was delayed in the pits.
The pair remained at the front during the next stint, but the key moment came when Dixon capitalised on one of the many caution periods to make his final stop under yellows and rejoin in third behind Power and Luca Filippi, both of whom still had a stop to make.
Their stops a short time later handed the lead back to Dixon, who put in an extraordinary lap on the final restart to open a gap of 2.7s over Simona de Silvestro in just one tour.
He added another 0.5s next time around, although the buffer would prove unnecessary when Mike Conway hit the tyres with three laps to go and forced the race to finish under yellows.
The effects of Dixon's win were magnified by a catastrophic weekend for championship rival Helio Castroneves, who woke up this morning with a 49 point lead, and goes to bed tonight with that advantage having been reduced to just eight.
The Brazilian qualified near the back, and then lost several laps in the pits having a gearbox problem attended to. He later lost more time to an array of minor incidents, but by that point it was academic.
Meanwhile, Conway's incident may inadvertently have cost his Dale Coyne team-mate a second place, as Justin Wilson was applying intense pressure to de Silvestro before the appearance of the yellows forced him to back off.
Third was still a strong result for the Briton considering that he had been forced to pit with a puncture halfway through the race.
But de Silvestro was equally good value for the runner-up position; the KV driver having spent the entire afternoon in the top five before securing her first career IndyCar podium.
Simon Pagenaud was fourth after a race spent mostly within striking range of the podium punctuated by one or two bad restarts, with Josef Newgarden rounding out the top five.
The final count of seven caution periods points to an eventful afternoon, with some of the most significant misfortunes affecting the Andretti camp.
James Hinchcliffe encountered a problem on the start and was hit by both Tristan Vautier and Ed Carpenter, while Ryan Hunter-Reay was one of many to fall victim to mechanical problems.
It was also a disastrous outing for polesitter Takuma Sato, whose miseries included an early puncture, a broken radio, and a trip into the tyre barriers.
Results - 90 laps:
Pos Driver Team/Engine Time/Gap
1. Scott Dixon Ganassi/Honda 1h54m48.3924s
2. Simona de Silvestro KV/Chevy +0.8781s
3. Justin Wilson Coyne/Honda +2.1432s
4. Simon Pagenaud Schmidt/Honda +3.5492s
5. Josef Newgarden Fisher/Honda +4.2293s
6. James Jakes Rahal/Honda +5.4614s
7. Graham Rahal Rahal/Honda +6.0983s
8. Sebastien Bourdais Dragon/Chevy +6.8946s
9. EJ Viso Andretti/Chevy +8.1873s
10. Luca Filippi Herta/Honda +9.3052s
11. Charlie Kimball Ganassi/Honda +9.9622s
12. Will Power Penske/Chevy +10.6455s
13. Marco Andretti Andretti/Chevy +11.1431s
14. Sebastian Saavedra Dragon/Chevy +1 lap
15. Dario Franchitti Ganassi/Honda +1 lap
Mike Conway Coyne/Honda 85 laps
Takuma Sato Foyt/Honda 82 laps
Helio Castroneves Penske/Chevy 80 laps*
Oriol Servia Panther/Chevy 63 laps
Ryan Hunter-Reay Andretti/Chevy 57 laps
Tony Kanaan KV/Chevy 34 laps*
Tristan Vautier Schmidt/Honda 32 laps*
Ed Carpenter Carpenter/Chevy 30 laps*
James Hinchcliffe Andretti/Chevy 1 lap
* Running again at chequered flag