Jeremy Lyverse, Associated Press
Mark Martin (5) passes Brad Keselowski (88) during the Nationwide race Saturday in Las Vegas.

LAS VEGAS — Mark Martin apologized. Carl Edwards and Brad Keselowski could do little more than smile, talk about their fine cars and walk away — disappointed.

With six laps to go in the Sam's Town 300 on Saturday, the three front-runners — Keselowski, Edwards and Martin, in that order — were headed down the straight when Martin bumped Edwards, who spun into Keselowski, who crashed.

Martin moved into the lead and after three laps under the caution, ran the last few laps to victory.

"First, I want to apologize. I didn't intend it to happen," he said.

"I went high and ran hard ... and got into the back of Carl, and once it started I couldn't stop it. I think everyone knows I give everyone the greatest respect. I made a mistake.

"I feel bad. I don't like to make mistakes. I have high standards, and there was some intense driving, really intense coming right down to the finish."

Martin, in fact, has a reputation of being one of the cleanest drivers on the circuit, which is why Edwards and Keselowski, a teammate of Martin's, held back any hard criticism. Martin is the winningest driver on the Nationwide circuit. Keselowski has yet to post a win.

"I don't think it was intentional," said Edwards, "but I saw a lot of crazy things out there today."

Martin, driving the Delphi Chevrolet, led for 81 of the 200 laps. He was leading when a yellow caution on lap 191 opened the door to the pits. He came back, and when the race was restarted, he was dropped back to sixth and was trying to get back into the lead when he bumped Edwards.

There was, in fact, a record number of caution flags. The old record was 12, and Saturday there were 13.

Drivers complained about the tires and the slippery track.

Many drivers were critical of the track last year after it was resurfaced and redesigned. They called it slippery and hazardous.

After Saturday's race, Martin called the track "awesome."

"Drivers were having trouble because the tires stuck so good and the race track is so fast that once the tires start slipping it's hard to gather back up, hard to keep the car under control. We saw a lot of that today," he said.

"The main thing is you've got to try and keep the car under you and not let it slip."

Other drivers also complained of tire problems.

"It's the wrong tire for here, it's too hard," said Kyle Busch, who crashed midway through the 200-lap event. "They're trying to slow us down, and everybody's wrecking. You even have experienced guys that are wrecking."

Busch, in the Interstate Batteries Toyota, was in the No. 2 position when a tire blew and threw him into the outside wall. At the time of the accident he'd led 18 of 104 laps.

He said he wasn't sure if the incident was caused by debris on the track or simply tire failure.

"I didn't see anything. I didn't feel anything. It's just unfortunate luck, I guess," he said.

Tony Stewart, in the Old Spice Toyota, was taken out of the race when he drifted up and caught David Rutimann in the Aaron's Dream Machine Toyota on the left-rear panel. Both cars spun out, but Stewart rolled up and smashed into the wall, causing extensive damage to the car. At this point he'd led 61 of the 139 laps and, after a pit stop, was charging back for the lead.

The main event, the UAW-Dodge 400, will start today at 2:30 p.m. with Kyle Busch in the M&M Toyota, the current NASCAR points leader sitting in the pole position. This is the third time he's started in front in 117 races.

His qualifying time around the 1.5-mile track was 29.613 seconds at 182.352 miles per hour.

Next to him will be Edwards in the Dish Ford with a time of 29.738 seconds at 181.586 mph; on the second row are Martin in the U.S. Army Chevrolet and Jeff Gordon in the DuPont/Nicorette Chevrolet.

Running under carmaker flags today are 13 Chevrolets, 13 Dodges, seven Fords and 10 Toyotas.

The race will be shown on ESPN2.