Josef Newgarden raced to his second IndyCar victory of the season Sunday, holding off rookie Pato O'Ward before a late caution ended the race at World Wide Technology Raceway under the yellow flag.
It's the second IndyCar race to finish under caution in one week. Takuma Sato won the Indianapolis 500 under yellow last Sunday.
In the second of two weekend races at the short oval outside of St. Louis, it was Sato who brought out the caution with four laps remaining when he hit the wall.
The pace car picked up the field with three laps remaining and IndyCar did not have enough time to restart the race.
It denied O'Ward a chance to challenge the reigning IndyCar Series champion for the victory.
Newgarden, in a Chevrolet for Team Penske, won for the 16th time in his career and closed the points deficit on championship leader Scott Dixon.
Dixon won Saturday in the first race of the Gateway doubleheader and has four victories in nine IndyCar races this season.
Newgarden and Team Penske have three wins.
Will Power had a shot at winning the race until his final pit stop, when he was slowed behind Ed Carpenter as both cars drove down pit lane.
Rinus VeeKay finished fourth and was met after the race by Colton Herta, who finished sixth but was angry at how the rookie had raced him late. Herta and VeeKay exchanged words.
with files from Associated Press