Kyle Busch fended off Mark Martin in a close finish to claim his fourth Sprint Cup win of the year on Saturday night at Bristol.
Martin had been the dominant force throughout the night until Jimmie Johnson passed him on lap 317 of the 500 scheduled. Later, the reigning champion ran into trouble with a loose right-rear wheel when the field pitted for the last time under caution on lap 423, being forced to pit again and giving Martin another chance to jump up front.
Michael Waltrip stayed out to lead the race while Ryan Newman jumped up to second by virtue of taking only two new tires. With a full new set of Goodyears, though, it was Busch who made the most of the outside lane on the restart to pass Martin and Newman and then grab the lead from Waltrip two laps later.
After that, four more caution periods provided further opportunities for Martin to attack Busch, but instead the 24-year-old seemed to profit from them all, opening a gap to the veteran who had to take every green flag after that from the inside lane, which proved to be a disadvantage on restarts all night long.
On the final four-lap sprint, Martin was able to stay clear in second place, and he took every opportunity to dive his nose on the inside of Busch's Toyota. The Joe Gibbs driver raced him clean, gave him room and in the end succeeded at keeping his momentum on the outside lane to win for the second time at Bristol this year.
"What a class act Mark Martin is, and he deserved to win this race," said Busch. "I'm sorry he came home in second."
"I drove as hard as I could, and he had a chance, and he could've done it, but he raced me clean. We didn't have the best car tonight, but we had a car capable enough of winning it."
This victory allows Busch to move up from 15th to 13th in the standing with just two races left before the Chase begins. Now, only 34 points separate him from Matt Kenseth's 12th place in the championship with Atlanta and Richmond coming - both tracks where Busch has won in the past.
Martin couldn't just get it done to celebrate his 1000th NASCAR start with a victory, but his second place was a big boost in the standings as he was able to jump up two places to 10th in the points battle, although still only 60 points ahead of 13th place.
"That was very exciting," Martin said about the closing laps of the race. "What can I say? Kyle gave me room and I didn't get the pass done. We were both racing hard for it and that inside was tough.
"I took my shot at it but just about slid up into him and wiped him out but I'm glad he gave me plenty of room there. I did everything I could, I wanted to get him but just couldn't pull it off."
Australian Marcos Ambrose impressed by finishing third purely on speed, claiming his best result on an oval at one of NASCAR's toughest venues. He could not quite get in the battle for victory in the end, but proved once again that he can be a contender beyond the road-course events, where he has always excelled.
Greg Biffle led the first portion of the race, then dropped down in the order with handling issues but recovered to finish fourth. Denny Hamlin was fifth at the flag, also recovering from a poor qualifying that left him nearly at the back of the grid and also from a puncture that put him a lap down early in the race.
Newman's tire gamble on his final stop allowed him to finish sixth ahead of Kurt Busch, who charged back from a multi-car incident ignited by contact between Sam Hornish and Casey Mears, who spun him around causing damage to the front end of his Dodge.
Johnson also recovered from the wheel problem on the final stop to take eighth ahead of team-mate Dale Earnhardt Jr, who was running fifth on the final restart but got shuffled back in the closing laps. Matt Kenseth rounded out the top-10 but still dropped one position in the drivers standing.
Points leader Tony Stewart had a race to forget, being hampered by radio communication issues and electrical problems. Jeff Gordon also had a rough day - but just like Stewart and Johnson, he is already locked in the Chase.
Of those still trying to secure a place in the play-off, the biggest losers were Juan Pablo Montoya and Kasey Kahne. Montoya ran a strong race until a flat tire forced him to pit under green and drop two laps down with just 35 to go.
The Colombian ran easily in the top-10 for most of the race and was running third when he started to struggle with the deflating right rear Goodyear, which cost him two places in the standings. Meanwhile Kahne ran in the midfield all day and his 28th place finish dropped him three positions in the points, down to 11th.
Clint Bowyer, Richard Childress Racing's only card to make this year's Chase this year, was involved in two separate incidents and has all but lost any chance of making it into the play-off this season.
1. Kyle Busch Toyota 500
2. Mark Martin Chevrolet 500
3. Marcos Ambrose Toyota 500
4. Greg Biffle Ford 500
5. Denny Hamlin Toyota 500
6. Ryan Newman Chevrolet 500
7. Kurt Busch Dodge 500
8. Jimmie Johnson Chevrolet 500
9. Dale Earnhardt Jr Chevrolet 500
10. Matt Kenseth Ford 500
11. Jamie McMurray Ford 500
12. Brian Vickers Toyota 500
13. Casey Mears Chevrolet 500
14. David Ragan Ford 500
15. Scott Speed Toyota 500
16. Carl Edwards Ford 500
17. David Reutimann Toyota 500
18. Jeff Burton Chevrolet 500
19. Reed Sorenson Dodge 500
20. David Stremme Dodge 500
21. Clint Bowyer Chevrolet 500
22. Martin Truex Jr Chevrolet 500
23. Jeff Gordon Chevrolet 499
24. Paul Menard Ford 498
25. Juan Montoya Chevrolet 498
26. Elliott Sadler Dodge 498
27. Regan Smith Chevrolet 498
28. Kasey Kahne Dodge 497
29. Scott Wimmer Chevrolet 496
30. John Andretti Chevrolet 494
31. Michael Waltrip Toyota 490
32. Robby Gordon Toyota 490
33. Tony Stewart Chevrolet 489
34. Joey Logano Toyota 484
35. Sam Hornish Jr Dodge 472
36. Bobby Labonte Ford 461
37. AJ Allmendinger Dodge 452
38. Kevin Harvick Chevrolet 438
39. David Gilliland Chevrolet 354
40. Terry Labonte Toyota 244
41. Joe Nemechek Toyota 48
42. Tony Raines Dodge 27
43. Dave Blaney Toyota 8