It was gut check time for Tony Stewart in Sunday's Sirius At The Glen NASCAR Nextel Cup Series race at Watkins Glen International - literally.

With his #20 Joe Gibbs Racing Home Depot Chevrolet proving dominant from the time he passed Jeff Gordon for the lead on just the second lap on the 2.45-mile road course, severe stomach cramps had Stewart wondering if he could simply finish - never mind win - the 90-lap race. And when Gordon re-took the lead from Stewart on lap 14, a relief driver was sought.

But after more laps of piloting a Home Depot Chevrolet that was clearly heads above any of the other 42 race cars on the track, Stewart bit the bullet and rallied to his third career road course win, his second of the season and the 19th of his Nextel Cup career.

"Physically, I felt good in the car as far as my strength went. I was just going through these stomach cramps," said Stewart, who started fourth after Friday's qualifying session was cancelled because of a wet track and the field was set by car owner points. "They'd get bad for a while and then they'd subside for a while. The good thing is that for the last 20 laps where I needed to be focused, that's the one part of the race where they went down a little bit. As soon as we took the chequered flag and slowed down they came again. I'm glad it was over when it was over."

Stewart led four times for 46 laps, the most of any driver, and beat road course ace Ron Fellows to the line by a solid margin of 1.517 seconds.

"I still felt the way I felt," said Stewart. "But there's no substitute for being in the lead. That's for sure."

Another road course standout was set to take the wheel of the #20 machine if Stewart opted out. Boris Said, who didn't make the field when qualifying was cancelled, was in a firesuit and standing by in The Home Depot team's pit. But after Stewart took the lead from Robby Gordon on lap 42, his decision to stay in the car was made.

"I knew that if it came down to it, Boris would do a good job in the car," said Stewart. "But everybody has different styles. The way I have my car set up may not be the way Boris wants it set up for him. Even though I knew we had a good car and had a good backup driver if we needed him, it's still not necessarily a perfect combination to put in a car like that. Knowing that we had such a good car was extra motivation to suffer through with it."

When Ward Burton blew his engine to bring out the fourth caution of the race, Stewart and fellow contender Jeff Gordon headed to pit road for their final stops of the race. And with 24 laps remaining, rookie Brendan Gaughan was the new leader with Casey Mears, Dave Blaney, Ricky Rudd and Stewart in tow.

On lap 68, Mears motored past Gaughan to take the lead for the first time, and with Stewart some 10 seconds back, Mears was in position to steal a victory by outlasting the rest of his competitors on fuel. But when Gaughan spun into the gravel trap on lap 72 to bring out a caution, Mears' cushion was erased.

When the race restarted on lap 76, Mears continued to lead, followed by Stewart, Blaney, Rudd and Fellows. But it took Stewart no time to pass Mears for the point. Fellows gave chase, but could only glimpse the orange bumper of Stewart's Home Depot Chevrolet as the race neared to a close.

"We had to work hard, but I just didn't have enough left for Tony after that last caution," said Fellows, who was followed to the line by Mark Martin, Mears and Dale Earnhardt Jr. "Obviously, we were second best."

Kevin Harvick, Jeremy Mayfield, Rudd, Matt Kenseth and Kurt Busch comprised the rest of the top-10. Stewart's Joe Gibbs Racing teammate Bobby Labonte finished just outside of the top-10 in 11th.

Stewart's win solidified his fourth-place standing in the championship point chase, but he was helped by the misfortune of those ahead of him. Series leader Jimmie Johnson suffered his second consecutive engine failure to finish 40th, and Jeff Gordon - who looked to have a top-five finish locked up - dropped to 21st after transmission trouble. That put Stewart 192 points arrears Johnson and 152 points behind second place Jeff Gordon. Third-place Earnhardt is 64 points up on Stewart. Fifth-place Matt Kenseth trails Stewart by 75 points.