With only five races remaining before the Chase for the Nextel Cup championship begins, Greg Biffle can’t afford many mistakes if he hopes to get in the competition.

However, he made a big one Friday. After being one of the fastest cars in practice on the road course at Watkins Glen, Biffle crashed during qualifying and will have to start at the rear of the field for Sunday’s AMD at The Glen.

“This car’s been a little bit loose,” said Biffle, who lost control of his No. 16 National Guard Ford going through the high-speed esses, the right rear slamming hard into the aqua-blue guard rail that lines the 2.45-mile course.

“Once these things break loose, you’re going through the esses at such a high speed, there’s not a lot of runoff room. There wasn’t any area for me to try to get a hold of it. I was driving it sideways, but it just got up in the guardrail.”

Biffle drove back to the pits, climbed under the back end to survey the damage, and shook his head in frustration.

“I feel bad, but our other car is just as good,” said Biffle, who will go off 41st in a backup car, his worst start of the season. “It’s the car we finished fourth with at Sonoma, so I feel really good about that.”

That bobble could put a big dent in his Biffle’s chances for the 10-race Chase because there aren’t many places to pass on the 11-turn layout. The top 10 in the standings — and any others within 400 points of the leader after the first 26 races — qualify, and Biffle sits 12th, 115 points behind 10th-place Dale Earnhardt Jr. and 627 behind series leader Jimmie Johnson.

“Track position is real important here,” said Earnhardt, who has three straight top-10 finishes at Watkins Glen. “You can be faster than a guy, but it’s real difficult to get close to somebody, let alone pass.”

Biffle’s two closest rivals in points will start on the front row. Kurt Busch, 13th in points and 59 behind Biffle, won his second straight road course pole with a speed of 122.966 mph in his No. 2 Miller Lite Dodge. That knocked Kasey Kahne (121.845 mph), who is 11th in the standings, to second.

It was the third pole of the season for Busch and sixth of his career.

“You’ve got to let it rip when you’ve got the chance,” said Busch, who posted the fastest lap in the final practice before his left front tire went flat and also had to wait to qualify after Sterling Marlin’s engine blew. “The crew gave me a car capable of sitting on the pole. I was just hoping to back up our time from practice, and we did that.”

Ryan Newman qualified third (121.642 mph), just ahead of four-time Watkins Glen winner Jeff Gordon (121.432 mph).

Johnson and Robby Gordon, who won here in 2003, will start on the third row, Kevin Harvick and two-time defending race champion Tony Stewart will go seventh and eighth, Kyle Busch and rookie Denny Hamlin round out the top 10, and Earnhardt will go 11th.

Kahne is 37 points behind Earnhardt, and just 171 points separate third from 11th place.

“There’s four guys in front of us in the mix,” said Busch, who also captured the pole at Sonoma in June. “I just have to keep the blinders on. We’re poised for a good run. Now we just need to go and do it.”

Kahne breathed a sigh of relief after qualifying and was well aware of Biffle’s trouble.

“I saw the mark he left when I went by, and it didn’t look good,” said Kahne, who crashed on the last lap a week ago at Indianapolis, finished 36th, and fell out of the top 10. “That could happen to any of us. We’re trying so hard through that part of the racetrack, and there’s not a lot of grip there.”

Kahne was oblivious to the turmoil surrounding his team, Evernham Motorsports. Team owner Ray Evernham announced early Friday that he had fired Jeremy Mayfield, driver of the No. 19 Dodge, on Monday.

Kahne just shrugged when asked about it. He had more important things on his mind.

Bill Elliott, who has been running a limited schedule since the end of 2003, was named to replace Mayfield on Tuesday and qualified 31st.