FONTANA, Calif. -- After Sunday's Auto Club 500, Greg Biffle went up to teammate Matt Kenseth and congratulated him in Victory Lane. But deep inside, Biffle knew he had given away a golden opportunity to win in the Golden State.

"I don't know how I'm going to sleep [Sunday night]," Biffle said. "I'm just sick to my stomach, man, it almost brings tears to my eyes to know that I let the guys down like I did. When you you've got a car like that, it sucks to not win, and it sucks that it's your fault. If they'd have dropped a lug nut or something, it wouldn't have been a big deal. But, when it's your fault, it's really hard."

Starting fifth, Biffle was a solid contender all race, watching and waiting while Jimmie Johnson, Jeff Gordon and Kenseth held the point. But it was obvious late in the going that Biffle had the car to beat -- if he could get track position.

After the fourth and final caution for nagging precipitation, Biffle started sixth when the field took the green on Lap 177. Within three laps, he went past Kyle Busch for fifth. Ten laps later, he was third. And with 50 laps remaining, he had passed Kenseth and seemed to be closing in on Gordon.

Kevin Harvick then hit the wall on Lap 208, bringing out what would be the final caution of the evening. One lap later, the leaders hit pit road for their final adjustments, with Gordon first and Biffle second.

With an opportunity to grab much-needed track position with a quick stop, Biffle gambled -- and ultimately lost. He carried extra speed into the pit box, hoping to shave a split-second off the stop. Instead, that caused him to slightly overshoot his marks, leaving his front tires on top of the air hose. The team was forced to pull the No. 16 Ford back to release the hose, a move that cost Biffle nine precious spots on the track (watch video).

"You know, it was so hard to pass out here, and I was hoping to beat [Gordon] out and I was trying to give my guys every advantage I could," Biffle said. "I stopped in the box, I wasn't out of the box, but the guy pulled the hose around, and we had this problem before. It's just me stopping too deep in the box and caught them off-guard and ran over the hose. And this box is super-long, anyway. But they didn't do anything wrong, it was my fault."

Biffle restarted just outside of the top 10, but with a double-file restart and only 35 laps to go, he couldn't navigate traffic quickly enough to challenge the leaders. He rallied back to fourth, a satisfactory finish but not the finish he expected -- or wanted -- particularly coming off a 20th-place effort at Daytona one week ago.

Still, Biffle's teammates were there after the race to lend their support.

"The guys know I'm feeling bad, but they're trying to keep me cheered up for next week," Biffle said. "They know we can win at Las Vegas. I'll keep working on it. I'm just mad because it always seems like I make a mistake, a little mistake here or there. I got in a little hot during qualifying and probably could've been on the pole -- maybe. Just little stuff. I'm too hard on myself, probably, I guess."

If there's a silver lining in the dark cloud hovering over Biffle after California, it's that if Sunday's race is any indication, errors might be the only thing that could slow down the No. 16.

"Yeah, they're [in trouble] if this is the kind of car I'm going to have all year," Biffle said. "This thing was fast. Unbelievable. Unbelievable."

For Biffle, that was truly a pit stop not to be believed. And a winning opportunity wasted.

Video
• Lap-by-Lap | Race Rewind | Post-race reactions