Kevin Harvick fended off Kyle Busch to claim Richard Childress Racing's first win of the NASCAR Sprint Cup season, while Brad Keselowski moved into the Chase lead after Jimmie Johnson hit the wall in an eventful afternoon at Phoenix.
Keselowski now needs a 15th-place finish at Homestead in order to clinch his and Penske's maiden Cup title.
He was sixth on Sunday, whereas Johnson was classified 32nd having hit the wall due to a melted tyre bead that caused his right-front to deflate exiting Turn 4 on lap 236 of the scheduled 312.
Harvick, who started the weekend making headlines over a potential move to Stewart-Haas Racing in 2014, broke a 44-race winless streak by beating Joe Gibbs Racing's Busch on the penultimate restart, then keeping Busch and Denny Hamlin at bay in a green-white-chequered finish.
Busch had led most of the distance and looked set to claim his second win of the season.
But Harvick passed him on the outside when the green flag waved on lap 305, following a caution caused by Sam Hornish Jr's Penske Dodge crashing after an exchange with Stewart-Haas Racing's Danica Patrick.
As the white flag was about to appear, the caution came out again when Jeff Gordon retaliated for a previous incident with Clint Bowyer. Both hit the wall and collected Joe Gibbs Racing's Joey Logano. Keselowski watched the action unfold right in front of him.
During the subsequent red flag, Bowyer and Gordon's crews got into a fight when Gordon got out of his car.
As soon as Bowyer parked, the Michael Waltrip Racing driver ran towards Gordon's Hendrick hauler in pursuit of his rival but officials prevented the feud from getting any further.
When the race resumed, Harvick not only had to fight Busch's Toyota for the lead but also cope with a slick track that would see him drift sideways out of the final turn to take the chequered flag as chaos unfolded right behind.
Greg Biffle got sideways on the slippery asphalt and hit Furniture Row's Kurt Busch, causing a multi-car incident that also involved Patrick, who was running slowly ahead of them following contact with RCR's Jeff Burton and the wall on the penultimate lap.
"You can't throw the caution flag as fast as you can throw it one time and then let everybody run through a whole straightaway full of oil," said a critical Harvick about the final restart.
Keselowski was caught up in the final incident, Kurt Busch ending up hitting the side of the #2 Penske after he struggled on the restart.
Hamlin eventually got second from his team-mate Busch in the end. Kasey Kahne finished fourth and moved up to third in the Chase, making the most of Bowyer's troubles, although both are now out of title contention.
Despite being involved in the final incident and spinning out of the last turn, Ryam Newman rounded out the top five.
Results - 319 laps:
Pos Driver Team/Car Time/Gap
1. Kevin Harvick Childress Chevrolet 2h52m09.000s
2. Denny Hamlin Gibbs Toyota + 0.580s
3. Kyle Busch Gibbs Toyota + 0.765s
4. Kasey Kahne Hendrick Chevrolet + 1.017s
5. Ryan Newman Stewart-Haas Chevrolet + 2.252s
6. Brad Keselowski Penske Dodge + 2.446s
7. Greg Biffle Roush Fenway Ford + 2.755s
8. Kurt Busch Furniture Row Chevrolet + 2.949s
9. Paul Menard Childress Chevrolet + 2.967s
10. Mark Martin Waltrip Toyota + 3.220s
11. Carl Edwards Roush Fenway Ford + 3.316s
12. Juan Pablo Montoya Earnhardt Ganassi Chevrolet + 4.214s
13. Jeff Burton Childress Chevrolet + 4.905s
14. Matt Kenseth Roush Fenway Ford + 5.526s
15. Bobby Labonte JTG Daugherty Toyota + 5.691s
16. Aric Almirola Petty Ford + 13.452s
17. Danica Patrick Stewart-Haas Chevrolet + 1 lap
18. Marcos Ambrose Petty Ford + 1 lap
19. Tony Stewart Stewart-Haas Chevrolet + 1 lap
20. Travis Kvapil BK Toyota + 1 lap
21. Dale Earnhardt Jr Hendrick Chevrolet + 2 laps
22. Casey Mears Germain Ford + 2 laps
23. Jamie McMurray Earnhardt Ganassi Chevrolet + 2 laps
24. Regan Smith Phoenix Chevrolet + 3 laps
25. Landon Cassill BK Toyota + 3 laps
26. Dave Blaney Baldwin Chevrolet + 3 laps
27. Joey Logano Gibbs Toyota + 7 laps*
28. Clint Bowyer Waltrip Toyota + 7 laps*
29. Timmy Hill FAS Lane Ford + 7 laps
30. Jeff Gordon Hendrick Chevrolet + 10 laps*
31. Sam Hornish Jr Penske Dodge + 20 laps*
32. Jimmie Johnson Hendrick Chevrolet + 38 laps
David Ragan Front Row Ford 280 laps
David Stremme Inception Toyota 86 laps
Stephen Leicht Circle Sport Chevrolet 74 laps
David Gilliland Front Row Ford 50 laps
Josh Wise Front Row Ford 50 laps
Michael McDowell Parsons Ford 36 laps
Joe Nemechek NEMCO Toyota 30 laps
David Reutimann Xxxtreme Ford 28 laps
Mike Bliss Humphrey Smith Toyota 15 laps
Jason Leffler Humphrey Smith Toyota 10 laps
Martin Truex Jr Waltrip Toyota 10 laps
* Not running at finish