Simon Pagenaud tells Ryan McGee about the incredible month he's had, between winning the Indy 500 and the Indianapolis Grand Prix. He also shares just how grateful he is. (1:48)

INDIANAPOLIS -- Simon Pagenaud arrived at Indianapolis Motor Speedway this month with his job on the line and rumors swirling around Gasoline Alley that Alexander Rossi could soon replace him at Team Penske.

The Frenchman is leaving with a pair of wins, his face soon to be engraved on the Borg-Warner Trophy as the Indianapolis 500 champion and an assurance from Roger Penske himself that he isn't going anywhere.

"Do I even have to answer that?" Penske asked. "Absolutely."

In a head-to-head duel for the ages, Pagenaud defeated none other than Rossi with a dramatic pass on the penultimate lap, then held on the rest of the way to hand Penske his 18th win in "The Greatest Spectacle in Racing." Even sweeter, it came on the 50th anniversary of Penske's arrival at the Brickyard.

Pagenaud and Rossi swapped the lead five times over the final 13 laps, and the margin of victory was a mere 0.2086 seconds -- the seventh-closest finish in the 103 years of the race.

"It's a dream come true. A lifetime trying to achieve this," said Pagenaud, who dismissed the premise of job security as he celebrated his first Indy 500 win. "The milk motivated me. I was just focused on the job, man."

Pagenaud was dominant all day, leading 116 of the 200 laps, and the win was cathartic. He stopped his car at the start-finish line and hopped out to share the moment with his fans. And once he finally made his way to victory lane, Pagenaud climbed from his car and let out a primal scream, then dumped the entire bottle of milk over his head.

"I never expected to be in this position," Pagenaud said, "and I certainly am grateful."

President Donald Trump phoned Penske in victory lane from Japan, where he was meeting with Prime Minister Shinzo Abe over trade. Penske passed the phone to Pagenaud, and Trump later tweeted an invite to the White House for the winning team.

Penske, who was there earlier with Joey Logano last month to celebrate last year's NASCAR Cup Series championship, said Trump told him: "I must have been your good-luck charm."

Simon Pagenaud won his first Indy 500, making an audacious pass of Alexander Rossi before taking the white flag. AP

Penske now has two consecutive Indy 500 victories -- Will Power won last year -- for the first time since 2002-03. It was his third win in the crown jewel race in the past five years and fifth in the past 14.

It was a banner day, too, with Josef Newgarden finishing fourth and Power in fifth.

Rossi lost his cool several times in the race, but the Californian had better fuel mileage than Pagenaud and the Penske cars. The 2016 race winner twice charged to the front in the closing laps.

"Horsepower. That's unfortunately the way it is," said Rossi, who was in a Honda for Andretti Autosport. "I think we had the superior car. We just didn't have enough there at the end."

Pagenaud was in a Chevrolet, and the bowtie brand was the dominant engine all May. It swept the top four spots in qualifying, won the race and took four of the top six spots.

Pagenaud is the first Frenchman to win the Indy 500 since Rene Thomas in 1914. Indianapolis records count five French winners, but Gil de Ferran in 2003 and Gaston Chevrolet in 1920, while born in France, list other nationalities. Pagenaud was the 21st winner from the pole and first since Helio Castroneves a decade ago.

As he began the traditional victory lap in the back of a convertible, Rossi was one of many drivers to walk onto the track to congratulate him. The American leaned in for a genuine embrace.

"Nothing else matters but winning," Rossi said. "This one will be hard to get over."

Rossi, who drove from the back to finish fourth a year ago, had been patient through the first half of the race and set himself up to take control after the halfway point. But a troublesome fuel hose on a pit stop caused a lengthy delay, and Rossi was angrily pounding his steering wheel while imploring the Andretti crew to get him back on track.

He really lost his cool when he couldn't get past the lapped car of Oriol Servia. As Rossi finally raced by, he angrily raised his fist at the Spaniard. A late wreck then caused an 18-minute stoppage with Rossi set to restart the final sprint as the leader, and he conveyed his mood over his team radio.

"A bunch of hungry, angry cars behind me," Rossi said. "Little do they know I'm angrier."

Pagenaud got him on the restart, though, and the two went back and forth four more times before Pagenaud locked down the win. Former champion Takuma Sato finished third as he and Rossi gave Honda two spots on the podium. Santino Ferrucci in seventh was the highest finishing rookie.

Attention had been heavy on rookie Colton Herta, but the 19-year-old driver for team owners Mike Harding and George Steinbrenner IV was the first driver out of the race when his gearbox broke.

Indianapolis Motor Speedway officials had prepared for rain, and perhaps even a postponement, in NBC's debut as broadcaster. But it was a bright, sunny day -- a picture-perfect showcase for Pagenaud to triumph on Memorial Day weekend.