HAMPTON, Ga. — Brad Keselowski was so sick at Atlanta Motor Speedway that his team had a standby driver on call.

The help wasn’t needed.

The winningest driver in Team Penske history raced to an unlikely victory Sunday, recovering from a stomach virus to win at Atlanta Motor Speedway. It was the first victory for Ford’s new Mustang, and a rebound for the manufacturer after Toyota swept the season-opening Daytona 500.

NASCAR debuted its new competition package Sunday that is designed to improve the on-track product and help smaller teams contend. The first look at the new rules was tempered, however, because the abrasive Atlanta asphalt is unlike any other surface NASCAR will race on this season.

Still, NASCAR has designed a package that slowed the cars and bunched them closer together, which made for intense racing when the field was packed on restarts. The nature of Atlanta’s challenging 1.5-mile track led drivers to eventually fan out into single file, which NASCAR is trying to avoid, but the racing is expected to improve moving forward.

“I saw a fairly entertaining race,” said Steve O’Donnell, NASCAR’s chief racing officer. “We didn’t know what to expect, either, and we thought this package would showcase itself more once we got to the West Coast. All in all, we are satisfied with the outcome and we’ve got a lot of work to do to go back and review it.”

Keselowski, meanwhile, raced to his 60th win for Roger Penske to pass Indianapolis great Mark Donohue’s mark as the team leader. He has won 27 of his 28 Cup victories for Penske.

“Oh, yeah, I forgot about that!” Keselowski said. “I think any win means a lot, but that’s a big number. Now I get to wear that yellow Mark Donohue helmet. This day is, wow, I don’t even know how to put it in words.”

Roughly six hours earlier, crew chief Paul Wolfe wasn’t even sure Keselowski could go the full 500 miles.

“He said he’s good to go, so we’ll see,” Wolfe said as he entered the prerace driver meeting.

Keselowski arrived shortly after, hopped off a golf cart and jogged into the meeting. Asked if he felt healthy enough to race, he said only: “I’m here, aren’t I?”

Keselowski has proved his toughness before, most notably in 2011 when he won at Pocono just days after breaking his ankle in a crash while testing. This time, he fell ill late Friday night after surprising fans in the Atlanta infield with beer during their rainy night of partying.

Keselowski’s wife was also sick, and Keselowski missed the start of Saturday’s final practice as Austin Cindric turned laps in the No. 2 Ford. Keselowski was able to complete two runs before practice ended, but medical workers took him via golf cart from the garage to receive treatment.

“I’ve got to give a lot of credit to my wife. She was sick just like I was, and she took great care of me, (as did) everybody in the care center,” Keselowski said. “I couldn’t be here today without them. So thank you.”

Martin Truex Jr. finished second in a rebound from his disappointing debut with Joe Gibbs Racing. His three JGR teammates swept the podium at Daytona, while Truex failed to contend. He was unhappy after this race because he said lapped traffic slowed his shot at catching Keselowski.

“Just a little upset,” Truex said. “We had the best car. We probably should have won that one.”