Alex Palou of Chip Ganassi Racing won IndyCar's GMR Grand Prix at Indianapolis on Saturday to take over at the top of the championship standings.
Spain's Palou won by 16.8 seconds from Arrow McLaren's Pato O'Ward with Arrow's Alexander Rossi finishing third.
Denmark's Christian Lundgaard, who had claimed his first IndyCar pole, had to settle for a season-best fourth place finish on the road course at Indianapolis Motor Speedway.
Starting third on the grid, Palou's first victory of the season came after he made a decisive start, powering his Honda into first place on the opening lap.
Making smart use of tire changes, Palou then took control when he overtook Lundgaard on Lap 42 to grab a lead which he never looked in danger of losing.
Palou praised his team for their pit and tire strategies including starting on the Firestone alternate "red" tires.
"What an amazing job by the crew. First win with them so I am super happy. We honestly knew we had a fast car since P1 (practice) yesterday.
"The car has been amazing all weekend and once we knew that we were starting on reds, I think we knew that we were going to fight for the win. Amazing work by these guys. I just had to execute," he said.
It was a positive day for Ganassi with New Zealand's Scott Dixon sixth and Sweden's Marcus Ericsson eighth.
Mexican O'Ward finished runner-up for the third time this season and accepted he had been well beaten.
"Hats off to them," he said. "I just think they were extremely strong today. They really were. But for us, I mean we're two, three and five as a team. I mean, that's pretty freaking phenomenal and you know the guys gave us a great race car."
The racers return to Indianapolis for the 107th running of the Indianapolis 500 on the Brickyard oval on May 28.
sev/bb
