Scott Dixon had to settle for fourth place, while Scott McLaughlin took an impressive eighth-place finish at IndyCar's Xpel 375 in Fort Worth, Texas.
Championship leader Dixon led for the majority of the 248 lap race after starting from pole position, only to ceede top spot behind a safety car, having just emerged from the pits as the day's third yellow flag was waved.
Despite having led, Dixon wasn't able to regain first place, and agonisingly missed the podium by one place.
McLaughlin took his second top-ten finish of the weekend, having come home for a second-place finish on Sunday, his maiden IndyCar podium.
Mexico's Pato O'Ward drove home to take his maiden IndyCar victory, and earned himself a Formula One test drive, thanks to a bet made with McLaren boss Zak Brown.
The 21-year-old bet Brown that if he won an IndyCar race this season, he would be allowed a test drive in an F1 car later this year.
O'Ward is the fourth different driver to win a race this season, behind Dixon, Alex Palou and Colton Herta.
Both Kiwis avoided a crash on the opening lap, which saw six drivers forced to retire.
Josef Newgarden finished second to O'Ward, while Graham Rahal completed the podium in third place.
Despite the result though, Dixon leads the drivers championship by 22 points, ahead of the now second-placed O'Ward.
McLaughlin meanwhile is eighth in the championship, four races into his rookie season after the move from V8 Supercars.
The next IndyCar race is the GMR Grand Prix in Indianapolis on May 16 (NZ time), before the Indy 500 on May 31.