WATKINS GLEN, N.Y. -- Marcos Ambrose missed his daughter's first day of school. She probably won't mind.
The snakebitten Ambrose, deprived more than once of a NASCAR victory, beat Brad Keselowski and Kyle Busch on a two-lap dash to the checkered flag Monday to win the rain-delayed Sprint Cup race at Watkins Glen International.
It was his first victory in 105 starts in NASCAR's top series and atoned for a slip-up a year ago on the road course at Sonoma, when he stalled his car under caution while leading with six laps to go and finished sixth.
"I've tried for 2½ years," Ambrose said. "We're going to onward and upward from here. It's a proud day."
Ambrose has won all three Nationwide races he's entered at Watkins Glen, and in three Cup starts here, he's notched one second and two thirds, including an impressive drive from last to third in 2008.
Finally pulling into Victory Lane was a feeling like no other.
"This is almost surreal," the affable Australian said in his No. 9 Ford for Richard Petty Motorsports after crossing the finish line.
Ambrose signed a multiyear deal with struggling RPM a year ago to drive the No. 9 this season. That capped a tumultuous summer in which he opted to leave the No. 47 at JTG Daugherty Racing at the end of 2010 with one year left on his contract, even though he knew he was taking a big risk in difficult economic times.
"There were days, weeks when I was anxious," Ambrose said. "There were times I was sitting around the boardroom table and there was nobody else there. But you've got to roll the dice sometimes."
It was Ford's first victory on a road course since Geoff Bodine won here in 1996 and the 15th different winner in Cup races this year.
Busch, trying to win a second time from the pole at Watkins Glen, led the field to the green flag for the final two laps. But Keselowski, racing with a broken left ankle and trying for his second straight win and third of the season, dove from third to the lead entering the first turn with Ambrose also streaking past Busch.
"Those guys didn't care to give me any room," said Busch, who finished second to brother Kurt here in Saturday's Nationwide race. "There's only one corner you've got to make, and as soon as you make it through that corner and can keep everybody behind, it's smooth sailing from there."
Ambrose then closed on Keselowski in the chicane after zooming through the high-speed esses and passed him for the lead before the final lap.
"I wanted to win," said Keselowski, who has the first wild card for the Chase and moved up four spots in the standings to 14th. "We had a shot at it, and that's all you can ask as a driver."
Kurt Busch, who won at Sonoma in June, crashed early and finished 38th. He wasn't alone: Denny Hamlin, who entered the day 11th in points, also crashed and finished 36th; five-time Watkins Glen winner Tony Stewart, who ran up front all race, was taken out on the final lap in the chicane and finished 27th; and Paul Menard, also in the hunt for a spot in the Chase, brought out the race-changing caution when he crashed on the 86th lap and finished 32nd.
The top 10 drivers in the standings and the two drivers with the most victories in 11th to 20th place earn spots for the 10-race Chase.
Keselowski never got the chance to challenge for the win on the final lap. The race ended with a caution as David Reutimann and David Ragan crashed violently entering the second turn, with Ragan slamming head-on into the guard rail and Reutimann's car bouncing hard off the barrier and sliding upside down across the track.
Ambrose was on a conservative pit strategy all day despite threatening weather -- the race was postponed by rain Sunday and more was in the forecast. He passed Truex for third on turn one, a 90-degree right-hander, of lap 73 and moved up to the bumper of Keselowski.
Ambrose then outbraked Keselowski going into the first turn on lap 76 and set his sights on Busch. He moved within three car lengths on lap 80 as the two encountered lapped traffic and closed to Busch's back bumper in the chicane with eight laps to go.
"Plenty of time to get him. Go get him," said Ambrose's crew chief, Todd Parrott.
Ambrose got the chance he wanted when Menard, running 14th, blew a tire and crashed on lap 86, bringing out the final caution.
That set up the frantic dash to the finish of what turned into a 92-lap race and spoiled the day for Kyle Busch, who led 49 laps. He was in the catbird seat for 18 straight circuits when Menard crashed.
"The last couple of laps I was getting away from him (Ambrose)," said Busch, who moved into a tie with Carl Edwards for the top spot in the standings. "The last thing I wanted to see was a caution -- knew it was going to come down to one corner and I messed up."
Hamlin brought out the third caution of the race on lap 67 when he zoomed at high speed straight through the first turn and slammed head-on into the tire barrier that borders the paved runout area.
Hamlin, who started at the rear of the field after a crash in qualifying and was all the way up to 11th, was not injured. But the stoppage jumbled the running order as Jeff Gordon gave up the lead to pit for the final time, giving Kyle Busch the lead again with Keselowski alongside him in the front row and Ambrose and Montoya in the third row.
"I had no brakes," Hamlin said. "I was trying to do everything I could. Just nothing you can do."