He climbed from his car and climbed the fence, same as he does after every win.
Then Castroneves darted across the street and patted the sign that was erected in Turn 10 earlier this month as a tribute to the fallen IndyCar star. He then emotionally doubled over against the wall, and seemed to be wiping tears away inside his helmet.
"No question about it, this is for our friend upstairs, Dan Wheldon," Castroneves said. "I used to stop in Turn 1 and celebrate, and this time I said I'm going to do something else in a different corner. I saw Turn 10, I didn't plan. As soon as I kind of celebrate, I look and I saw Dan's sign. It's amazing. It was a perfect fit for this race, a perfect way to start the season."
"I felt very touched by seeing his name there. What happened last year, we still hurt, but we've got to keep moving on."
The IndyCar Series finally returned to racing on Sunday, its first event since Wheldon was killed in last October's season finale. The opener was through the streets of St. Petersburg, the Englishman's adopted hometown, where his wife and two sons still live and where Wheldon won the inaugural 2005 race.
The pre-race ceremony included a tribute video of Wheldon, and his younger sister, Holly, dropped the green flag.
"I think it is still so fresh and I think in some ways it's almost fitting the first race was in St. Pete," runner-up Scott Dixon said. "For me, personally, I just miss the guy. It sucks not to be able to turn around and see him coming through a door with those bright white teeth sort of smiling at you. It's tough to deal with."
The race itself was somewhat anticlimactic, with Castroneves' bold pass of Dixon 27 laps from the finish one of the few memorable moments on track. But a nice, clean, race was probably just what IndyCar needed after the horrific 15-car accident that killed Wheldon at Las Vegas Motor Speedway.
With a five-month layoff after the accident, Wheldon's death haunted the series and halted any sense of normalcy for the drivers.
So even after finally getting a race in the record books, Wheldon was still on everyone's mind.
"Most of all we are missing Dan," said third-place finisher Ryan Hunter-Reay. "That wound is still fresh and this race would have been better with him in it, that's for sure. He was just such a great ambassador for our sport. He was a champion and all of us want to emulate him. We all want to be like him.
"We love the Wheldon family. This is their city."
That's been the theme this entire weekend, and it overshadowed everything IndyCar brought into this new season.
IndyCar welcomed multiple engine manufacturers Sunday with Chevrolet and Lotus joining Honda, and the introduction of the first new car since 2003. Because he was without a full-time ride last season, Wheldon was the development driver for the new car and Dallara named it the DW12 after his death.
It was designed to upgrade both technology and safety measures, and Castroneves believed it might have made a difference in the season finale.
"This car we had today, unfortunately, it came just a little too late," he said. "If we did have this car in the last race of the season, I believe Dan would be here."
The new car wasn't put through much of a safety test on Sunday; Castroneves' spin of Ed Carpenter, and James Jakes running into the tire barrier in Turn 10 were the only two caution-causing incidents.
Instead, attrition was the issue, beginning 11 laps in when the Lotus driven by Katherine Legge inexplicably stopped on the track. All eyes have been on Lotus this off-season because the manufacturer is admittedly behind the competition and didn't even get an engine to Sebastien Bourdais until late Thursday afternoon.
Alex Tagliani of Lachenaie, Que., and Oriol Servia were the only two Lotus drivers still running at the end of the race, and finished 15th and 16th, one lap down.
Bourdais, who was decent in the middle of the race, Legge and Simona de Silvestro all retired with mechanical problems.
The other two manufacturers weren't immune. Tony Kanaan went out with a mechanical issue 21 laps into the race, and a fuel-pressure issue also knocked out fellow Chevrolet driver JR Hildebrand. A gear problem sidelined Honda driver Mike Conway.
Pole-sitter Will Power was done in by strategy that backfired — the Penske team brought him into the pits during the early caution for Legge, and the loss of track position took him out of contention. He spent most of the race mired in traffic and was grateful to leave with a seventh-place finish.
"That was the worst race of my life," he said. "I had the best car I've ever had, it was so fast, and we just got shuffled back there after that first pit stop and we just couldn't make up the ground we needed. It was very tough to pass."
Dario Franchitti, the defending series champion and race winner, was 13th after running out of gas on the final lap. Even so, he never contended and was already thinking about next week's race at Barber Motorsports Park.
"We didn't have the best day," he said, "but we'll do some work and be back strong at Barber."
Former Formula One star Rubens Barrichello was 17th in his IndyCar debut, and said he also ran out of gas at the end of the race.
"I enjoyed the race and dicing with other cars, but would have liked to have been able to push more," he said. "It has been a good learning experience this weekend and I look forward to being back in the car in a few days for the next race."
Toronto's James Hinchcliffe, who was not entered in this race last year, finished fourth in his debut race for Andretti Autosport in Danica Patrick's old ride. Penske's Ryan Briscoe was fifth and was followed by Simon Pagenaud, who had to start 16th after making an unproved engine change on Friday.
Power was seventh and E.J. Viso and was followed by Charlie Kimball and Justin Wilson.
Josef Newgarden wound up 11th in his IndyCar debut.