Fuel conservation was the critical factor during Friday night's Feed the Children 300 Nationwide series race at Kentucky Speedway, and it was Brian Keselowski who had it figured out the best.

He made sure he was playing the fuel strategy game right from the final restart on lap 139, and as a result just had enough gas in the tank to crawl over the finish line 61 laps later just ahead of his only real rival on the night, Kevin Harvick.

Keselowski's win thwarts Kyle Busch's hopes of claiming a triple crown this weekend at Kentucky. Busch had won Thursday night's UNOH 225 Camping World Truck Series race and is on pole position for Saturday night's Quaker State 400 Sprint Cup race after qualifying was rained off, but his trifecta hopes were dented when he crashed his Nationwide car in qualifying and ended up starting from the back of the field in a backup car. Even so, Busch battled back to finish in third place ahead of Kasey Kahne.

Elliott Sadler finishing fifth, having led from pole position for the first eight laps before Harvick took over for all but one of the next 56 laps; but once Keselowski took the lead on lap 68 no one could get past him except for brief overlaps during pit stop sequences, and he went on to lead for a grand total of 132 of the 200 laps.

Keselowski admitted that the clean air up front had been critical for him. "I certainly felt more comfortable once I got clean air," he said. "You get that clean air, and these cars are just phenomenal to drive, and mine was no exception. It was really, really fast."

As for managing to make the fuel last, know what speed he could get away with and still make it to the end of the race, Keselowski insisted that there was no special gadget or formula for working it out and it all came down to instinct - or, as he put it, flying by the seat of his pants.

"I like to say it's a special gauge we put in the car - I call it an assonometer," said Keselowski. "It's my ass. That's my gauge."

His fuel strategy left others shaking their heads and wondering what his and Penske's secret was.

"We had a car to win, we just are getting beat on this fuel mileage stuff every week," said Ricky Stenhouse Jr. who finished in ninth place. "We are just going to have to go to the shop and figure it out. They are just killing us on those and have the car to win, we just can't do it without the fuel mileage."

The win is Keselowski's 13th in 156 Nationwide starts and his first at Kentucky in four starts. It's Penske's 17th series win and their first at Kentucky and also their first in 2011, emphasising once again just how much of a rebound they've pulled off in the past month across the board.

There were a total of five cautions during the race. The first was caused by a tyre blow-out on Ricky Stenhouse Jr.'s #6 on lap 44; a crash in turn 4 for Will Kimmel on lap 66; contact between Brian Scott and the lapped car of Robert Richardson Jr. on lap 101; contact between Charles Lewandoski and Morgan Shepherd at the restart on lap 107; and then a final caution on lap 134 when Robert Richardson Jr. got into the wall and sustained heavy rear-end damage.

That yellow was the one under which everyone pitted, right on the edge of any realistic hope of making it to the end of the race on that tank of gas. Many drivers including Mark Martin, Brian Scott, David Reutimann, Reed Sorenson and Jason Leffler all had to pit again in the final few laps, and even Kevin Harvick flirted with taking to pit road before being ordered to stay out to the bitter end come what may.

Full race results are available.

The next race is at New Hampshire Motor Speedway next Saturday, July 16.