Fontana, CA (Sports Network) - Defending Sprint Cup Series champion Tony Stewart picked up his second win of the season with a lot of help from Mother Nature on Sunday at Auto Club Speedway.

With showers on the way to the two-mile Southern California racetrack, Stewart passed Kyle Busch on lap 85 of the scheduled 400-mile race. He held the lead when the rain arrived on lap 125, forcing the first and only caution.

During the caution, Stewart appeared to be making a pit stop along with all of the other frontrunners, but Stewart faked second-place Denny Hamlin at the last second and veered back onto the track. Hamlin, the pole sitter, passed the commitment line on pit road and was forced to stop, as did Jimmie Johnson, Matt Kenseth and Mark Martin. Busch also decided not to pit and moved into the second position.

The rain intensified shortly after, prompting NASCAR officials to halt the Auto Club 400 after 129 of 200 laps were completed. Officials then called it 30 minutes later.

"You hate to have them end with rain like that. but I've lost some that way," Stewart said. "The good thing is that we didn't give up the lead because we stayed out and the leaders came in. We were leading the thing and had earned that spot."

This was the first Sprint Cup race at this track to be shortened due to inclement weather. The last Cup event to be stopped short of its scheduled distance occurred in June 2009 at New Hampshire Motor Speedway. Then rookie Joey Logano won that race.

Stewart claimed his 46th career victory, which placed him in a tie with Buck Baker for 14th on the series' all-time race winners list.

All five of Stewart's victories last year came during the 10-race Chase for the Sprint Cup championship. Stewart finished the season in a points tie with Carl Edwards but won his third series title by virtue of his five race victories compared to only one for Edwards.

Stewart normally doesn't start winning races in the series until the second half of the season. He has two in just the first five events this season. Stewart won at Las Vegas Motor Speedway for the first time earlier this month.

"It's been nice to get off to a good start this year the way we have," he said. "The history shows in the last 13 years we have not had the strongest starts the first third of the year. I'm really excited about the start that we've got going."

Busch, who led the most laps with 80, finished second.

"All in all, it was a really good day," he said. "I'm glad we were able to run that way and up front like we're supposed to and to our potential. We had a day where we didn't have attrition or something else get in our way."

Dale Earnhardt Jr. continues to have a strong start to the season with a third-place run at California.

"We had some really good pit strategies, pitting a little bit earlier than most guys," Earnhardt Jr. said. "We drove the car up to fifth before the weather came. We had been watching the weather all day and felt certain if it started to rain, it wasn't going to stop. We made the right choice by staying out and building ourselves into the top three."

California-native Kevin Harvick finished fourth in front of his home crowd. Harvick won this race one year ago.

Roush Fenway Racing teammates Carl Edwards and Greg Biffle finished fifth and sixth, respectively, while Stewart's teammate, Ryan Newman, took the seventh spot.

Martin Truex Jr. placed eighth, followed by Kurt Busch and Johnson, who hails from nearby El Cajon.

Johnson was running 10th when he pitted during the caution. After returning to the track, Johnson had smoke pluming from the back of his Chevrolet.

"Unfortunately, we had an oil leak," Johnson's crew chief, Chad Knaus, said after the incident occurred. "We're looking into it right now to see what happened there on that last pit stop. Something happened, and we developed an oil leak."

Johnson has finished 10th or better in the last 10 races at California. He holds the track record with five wins.

Hamlin wound up finishing 11th.

Biffle remained atop the point standings. He now holds a seven-point advantage over Harvick. Earnhardt Jr. is 17 markers behind the leader.

Stewart's win boosted him from seventh to fourth in the standings. He trails Biffle by 18 points.