Kurt Busch is undefeated in NASCAR Busch Series racing.

Beating Jeff Burton off pit road on lap 137, Busch took the lead and never looked back despite getting slowed down by six late race cautions and a green-white-checker overtime session.

Saturday was Busch’s first career start in the series, making him the fifth driver to win a Busch race on the first try. It also makes Busch the 16th driver to have a win in the truck, Busch and Cup series.

“It was a fun day to be a rookie and learn as I went,” said Busch.

Busch said the No. 39 team was established by Penske Racing as a farm team to train crew members for the NEXTEL Cup Series.

“This is exactly what a Busch program should be, a place where you can breed crew guys and develop them and be good in the Cup Series.”

Greg Biffle was the top Roush Racing driver, finishing second. Biffle said his car started the race very tight, but once his team made the proper adjustments, it was turned better and gave him a chance to get to the front.

“I had a couple of opportunities to get past Kurt and there were lapped cars on the side of me and I couldn’t get to the bottom,” Biffle said. “It’ so tough to pass the guy in front.”

Busch finally won the race by holding Biffle off during a green-white-checker finish. On the final scheduled lap, the caution was thrown after

Busch, who drives the No. 2 Miller Lite Dodge in the Cup Series, always referred to the minor-league series as the “Grand National Series,” its lesser-known nickname, to avoid saying the name of his Cup sponsor’s competition.

“That’s the name of it on the bottom of the sign,” Busch said.

NEXTEL Cup regulars finished in 12 of the 15 top spots. Paul Menard, driving for Dale Earnhardt, Inc., was the first non-Cup regular to cross the finish line, he took the seventh position.