INDIANAPOLIS (AP) — The forecast called for a potential washout of the Indianapolis 500, yet the fans still packed the Snake Pit, crowded the Midway and roamed Gasoline Alley hoping rain wouldn't ruin one of the most revered events in the world.

IndyCar, ever so slowly trying to race its way back into relevancy, had too much to offer in the 103rd running of "The Greatest Spectacle in Racing" and a weeklong prediction of terrible Sunday weather had everyone on edge. The pre-race pageantry absolutely had to happen and both IndyCar and broadcast partner NBC were desperately anxious to show the world their much-improved product without any weather disruptions.

But on a day that called for a 90 percent chance of thunderstorms, the sky over Indianapolis Motor Speedway remained clear blue and the Indy 500 went off without a hitch. It turned out to be the most perfect day for a breathtaking 500 miles full of chaos, drama and spectacular racing.

IndyCar's drivers have argued for years they have the most competitive series in the world, an argument impossible to be settled, but one put on display Sunday with a flashy showing of speed, danger, anger and a job-saving drive by winner Simon Pagenaud.

Pagenaud and Alexander Rossi traded the lead five times over a frantic final 13 laps, with Pagenaud determined to hold off the American rumored to be in line to replace him at Team Penske. Pagenaud made his final pass on the penultimate lap, then blocked Rossi for the final 2½ miles around the Brickyard. He took the checkered flag for a clean May sweep at Indy — he won the road course race three weeks ago, the pole for the Indy 500 and then the Borg-Warner trophy to earn a guarantee from team owner Roger Penske that Pagenaud is not getting fired at the end of the season.

"I was never going to give up," Pagenaud said. "That's what saved me, saved my career at one point. That's what always helped me, and I always believed. I've been saying it, but kids, if you're looking, if you're watching, always believe in your dreams.

"And if you really believe it, believe it hard, and if you work hard enough, anything can happen."

The overnight rating in NBC's debut of the race was up 15% compared with when ABC broadcast it for the 54th and final time. Viewership hit a high of 4.56 in the final 15 minutes of the Pagenaud and Rossi duel, and the network said it was its highest rating for a Sunday afternoon sporting event since an NFL playoff game the first week of January.

Although it was a milk-drenched Pagenaud celebrating Penske's 18th Indy 500 win, it was an overall victory for IndyCar, NBC, the speedway and anyone who watched. Rossi again captivated the audience with a dazzling drive around Indy and he was clearly on the edge. He banged his steering wheel in frustration when a problem with his fuel hose cost him track position, and he raised his fist in anger trying to pass the lapped car of Oriol Servia at 220 mph.

"Once you've won this thing once, the desire to win just ramps up exponentially every year," said Rossi, who won as a rookie in 2016 on fuel mileage. "It sucks to come this close and really have nothing that we as a team could have done differently."

Conor Daly, a promising young American unable to land the sponsorship to find a full-time job in racing, cracked the top five and settled for a career-best 10th-place finish. He is hopeful the run leads to more rides.

Santino Ferrucci, a rookie to the series and the speedway, was seventh in a trouble-free showing for another young American hopeful. Graham Rahal was running inside the top 10 until contact with Sebastien Bourdais knocked them both out of the race.

A furious Rahal rushed to Bourdais, who was still in his car, and seemed to lightly smack Bourdais' helmet in complaint of the contact. Rahal also raised his arms to the crowd, signaling for a rowdy cheer from the sun-drenched grandstands.

Bourdais had the luxury of a brand-new car team co-owners Jimmy Vasser and James Sullivan sprung for specifically for the Indy 500, and to see it crashed after running inside the top 10 all day was crushing. Sullivan buried his head in his hands when he saw the accident while watching on the pit stand.

Marco Andretti, still trying to break the Andretti curse at Indy on the 50th anniversary of grandfather Mario Andretti's only 500 victory, had an issue with his car on the first lap and his race was instantly ruined. He finished 26th.

Colton Herta, who became IndyCar's youngest winner days before his 19th birthday, didn't even get the chance to ride around. His gearbox broke just six laps into the race. And Helio Castroneves, still trying to win his elusive fourth 500, had contact with another car on pit lane and the penalty for contact took him out of contention.

All this went on without McLaren or Fernando Alonso on track. The mighty return of the brand was spoiled when McLaren failed to get Alonso into the field of 33, so their only presence Sunday was a merchandise trailer and hospitality suite.

Fans jammed the McLaren booth to grab discounted T-shirts and hats, while sporting director Gil de Ferran gamely entertained more than 100 sponsors and guests who had expected to watch the two-time Formula One champion zip around the speedway in the papaya orange car.

In missing the race, McLaren showed the Indy 500 is a beast of an event that can't be taken for granted.

And even with Alonso watching on TV somewhere, IndyCar proved that for at least one day of the year, it has the best product on the track.

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