WATKINS GLEN, N.Y. — Just when Marcos Ambrose had about given up hope of winning again at Watkins Glen International, he began to slide.

Suddenly in his element on an oil-smeared track, the Australian road race ace came alive one final time Sunday, storming past Kyle Busch and Brad Keselowski in a fender-slamming last lap of a chaotic Sprint Cup race to win at Watkins Glen International for the second straight year.

“It wasn’t going to be handed to me,” Ambrose said. “I had to get myself back up there.”

Ambrose, who led eight of the 90 laps around the 2.45-mile, 11-turn layout, had been shuffled back to ninth after a late caution and quickly made his way back to third in less than 10 laps, behind only Busch and Keselowski.

After passing Keselowski for second, Ambrose still trailed Busch by 2.3 seconds and figured he was running for second as the laps wound down.

“I managed to fight my way past Brad and then I tried to chase Kyle down, but he wasn’t making any mistakes and he had a fast car,” Ambrose said. “I just burned my stuff up trying to get to him. I was thinking, ‘OK, it may be second place here.’ But then the oil came down and I slipped to third and I thought, ‘That’s not the plan.’ So I just put my head down and just kept trying.”

Oil had begun spewing from the No. 47 of Bobby Labonte, and it coated much of the track. With only one lap remaining, NASCAR did not throw a caution and Ambrose capitalized.

“It was absolutely chaos at the end,” Ambrose said. “I had really burned off the brakes. I couldn’t figure out where it (the oil) was coming from. It was just absolutely crazy.”

Desperate for a win to move back into contention for the Chase for the Sprint Cup championship, Busch skidded wide coming out of the first turn of the final lap and was bumped by Keselowski’s fast-closing No. 2 Dodge.

“Busch slipped up big in turn one,” said Keselowski, who apologized after the race on Twitter. “There was nothing I could do. It was just one big giant oil slick underneath his car. We all checked up and Marcos was right on my bumper. We all just about spun out.”