Marcos Ambrose passed Brad Keselowski on the final lap, and then held him off in a fender-banging duel to win the Sprint Cup race at Watkins Glen International on Sunday for the second consecutive year.

Kyle Busch was in control but skidded on oil that had leaked on to the track and skidded sideways coming out of the first turn of the final lap. Keselowski's Dodge came off the side of Busch’s Toyota and Ambrose followed Keselowski through.

Ambrose and Keselowski battled side by side the rest of the way around the 3.9km circuit, with neither giving ground before Ambrose moved in front heading to the chequered flag.

Jimmie Johnson was third, followed by Sonoma winner Clint Bowyer and Sam Hornish Jr., giving Dodge two in the top five.

“It was absolute chaos at the end.”

Ambrose said: “I had really burned off the brakes. I couldn't figure out where the oil was coming from. It was just absolutely crazy at the end.”

The oil that had been spewing from Bobby Labonte’s car ruined the day for Kyle Busch, who seemingly held a commanding lead heading to the white flag of the Finger Lakes 355.

“In the end, nobody knew what was going on,” said Richard Petty, owner of Ambrose's Ford. “They were slipping and sliding off the race track. Marcos might have known a little bit about it, but the rest of us didn't. Marcos stayed with it all day. Everything fell our way.”

It didn't for Busch, who led 43 laps.

Busch's crew chief Dave Rogers siad: Kyle hit the oil. Labonte’s car broke. You can see him, he just went by smoking. He left oil all over the track. Kyle hit the oil and it allowed the Keselowski to get to us.”

Desperate for a win to move back into contention for the chase for the Sprint Cup championship, Busch skidded sideways coming out of the first turn of the final lap.

Keselowski, who suffered damage to the front of his car, said: “Busch slipped up big in turn one. There was nothing he could do. We all checked up and Marcos was right on my bumper. We all just about spun out. We got to the inner loop, and again nothing but oil.”

Ambrose slipped again in turn 10, but Keselowski couldn't drive past. Neither gave ground, and Ambrose forged ahead on the final turn, another hard right-hander, and turned away Keselowski's final charge on the outside.

“I thought I had him.”

“I must have hit the oil one more time and he didn't,” Keselowski said.

Busch was not available for comment after the race.

The top 10 drivers in the standings qualify for the 10-race Chase, and two wild cards are awarded to the drivers with the most wins outside the top 10 - provided they finish 20th or higher in points.

Polesitter Juan Pablo Montoya, who broke the track record in qualifying, finished 33rd after being forced to pit when something broke in the right front of his Chevy a third of the way into the 90-lap race. He had tracked Busch for the first 26 laps.- Sapa-AP