Scott Dixon closed the gap to championship leader Helio Castroneves to just nine points as he took his fourth win of the season.
The Kiwi had built up a lead of over three seconds in the closing stages but the race ended under caution, the seventh of the race, after a late race bump for Mike Conway.
Simona de Silvestro fought in the top ten all race long, eventually finishing second to claim the first podium of her IndyCar career. Brit justin Wilson finished third.
Whilst the win allowed Scott Dixon to maintain his championship challenge, points leader Helio Castroneves had a dismal race.
The Brazilian suffered from gearbox problems early on before languishing around towards the back of the pack as the race progressed, finishing 18th. His previous worst finish this season was 13th in Sao Paulo.
2012 Champion Ryan Hunter-Reay also hit gearbox trouble. He retired from the race on lap 60.
The race also saw the return of standing starts to the series after last being used int he double header event at Detroit. The first attempt was aborted after Charlie Kimball stalled on the grid. the second attempt ended in disaster after Ed Carpenter struck the stationary car of James Hinchcliffe after the Canadian also stalled on the grid.
The Grand Prix of Houston continues tomorrow with the second race of the double header event.