Marcos Ambrose has claimed his first ever NASCAR Sprint Cup win in a crash-marred finish at Watkins Glen.

Pitting Ambrose on lap 19, the Aussie's veteran NASCAR crew chief Todd Parrot elected early to run a three-stop strategy and stuck to the plan for the entire race.

A caution for the stricken car of Greg Biffle on lap 28 saw all but a handful of drivers pit, giving Ambrose the lead from Juan Pablo Montoya at the restart, but it was short lived, the #9 car returning to the pits on lap 38 and rejoining mired in 29th.

A second caution with 42 laps remaining set up a one-stop race for the entire field, with almost the entire pack heading to pit lane under green with 30 laps to go.

Staying out for an extra few laps gave Ambrose the lead from Montoya, the two race-favourites locked together on strategy and on track as they struggled to make enough ground to maintain the lead after their stops.

Harking back to the bad strategy that cost him dearly at Sears Point Ambrose asked his team not to 'do anything fancy' as he completed his final planned stop of the day.

Running 11th after that stop Ambrose needed a safety-car to bunch the field, and he got it on lap 67 when Denny Hamlin lost brake pressure and hit the wall head on at turn one. Ambrose was only metres away from being taken out by the out-of-control #11 car.

Hamlin escaped unscathed from the crash as the field lined up for a treacherous double-file restart with Ambrose on row three alongside Montoya.

When Ambrose passed Martin Truex Jr for third with 18 laps to go it left only Brad Keselowski and Kyle Busch between him and breakthrough NASCAR Sprint Cup win.

Keselowski himself had plenty to fight for, on the brink of a berth in the Chase after a courageous second win of the season in Pocono despite the broken ankle he suffered in a horror crash during testing just days earlier.

The battered and brave Keselowski was dispatched by Ambrose with 15 to go, and the Devil Racer set off after Kyle Busch for the lead.

The Stanley Tools-backed driver closed the 2.5 second gap to the infamous #18 within five laps, but was still beating on Busch's bumper when Paul Menard triggered a late-race caution with four laps to go.

The green-white-chequered finish saw Ambrose start on the outside of Busch, and it was an ugly start as Keselowski rounded up Ambrose, Busch ran wide and Keselowski took the lead from a hyper-aggressive Ambrose.

Kyle Busch snapped sideways but held on as they rounded the final turn for the penultimate time with Ambrose in the lead.

A monster crash for David Reutimann took the spotlight for a moment but as he clambered unhurt from his destroyed racecar Ambrose crossed the line in jubilation to record his maiden win.