Matt Kenseth claimed the early advantage in the NASCAR Sprint Cup Chase by winning a delayed Chicagoland race.
Heavy rain showers meant an event originally due to commence at midday local time finally finished at 11pm.
The start was delayed nearly two hours as efforts to dry the track took place, and then further rain forced a red flag stoppage of over five hours on lap 109 of 267.
Kenseth had usurped Jimmie Johnson atop the championship just as the points were reset at Richmond last week.
He and Joe Gibbs team-mate Kyle Busch made their way to the front during the 'daytime' segment of the Chicagoland race and led the majority of laps when it eventually resumed under the lights.
Busch was ahead at the final restart 20 laps from the end, and had a shot at sweeping the weekend following Truck and Nationwide wins.
But Kenseth got the better run at the green and took the lead, then established enough of a cushion to keep Busch at bay to the flag.
Richard Childress Racing's Kevin Harvick fended off Kurt Busch and Jimmie Johnson for third.
Both Harvick's pursuers had to fight back from pit delays. Busch was infuriated by a speeding penalty, while Johnson was erroneously held by an official suspecting a lugnut issue at his second stop and then later had a jack issue.
His team-mate Jeff Gordon came back from a puncture for sixth, followed by Brad Keselowski, Ricky Stenhouse Jr, Clint Bowyer and Ryan Newman.
Polesitter Joey Logano led early on but was one of several drivers to suffer an engine failure, a fate shared by fellow Chase contender Dale Earnhardt Jr and a very disgruntled Denny Hamlin.
Results - 267 laps:
Pos Driver Team/Car Time/Gap
1. Matt Kenseth Joe Gibbs Toyota 3h10m56.000s
2. Kyle Busch Joe Gibbs Toyota +0.749s
3. Kevin Harvick Childress Chevrolet +3.626s
4. Kurt Busch Furniture Row Chevrolet +3.808s
5. Jimmie Johnson Hendrick Chevrolet +4.704s
6. Jeff Gordon Hendrick Chevrolet +4.871s
7. Brad Keselowski Penske Ford +5.065s
8. Ricky Stenhouse Jr Roush Fenway Ford +6.856s
9. Clint Bowyer Waltrip Toyota +8.254s
10. Ryan Newman Stewart-Haas Chevrolet +8.712s
11. Carl Edwards Roush Fenway Ford +10.966s
12. Kasey Kahne Hendrick Chevrolet +12.236s
13. Aric Almirola Petty Ford +12.713s
14. Jeff Burton Childress Chevrolet +13.348s
15. Marcos Ambrose Petty Ford +14.700s
16. Greg Biffle Roush Fenway Ford +15.533s
17. Mark Martin Stewart-Haas Chevrolet +15.814s
18. Martin Truex Jr Waltrip Toyota +16.713s
19. Jamie McMurray Earnhardt Ganassi Chevolet +17.638s
20. Danica Patrick Stewart-Haas Chevrolet +18.499s
21. AJ Allmendinger JTG Daugherty Toyota +19.386s
22. Paul Menard Childress Chevrolet +20.085s
23. Dave Blaney Baldwin Chevrolet +23.877s
24. Travis Kvapil BK Toyota +1 lap
25. JJ Yeley Baldwin Chevrolet +1 lap
26. David Ragan Front Row Ford +1 lap
27. Justin Allgaier Phoenix Chevrolet +1 lap
28. David Gilliland Front Row Ford +1 lap
29. Landon Cassill Hilman Chevrolet +1 lap
30. Casey Mears Germain Ford +1 lap
31. Joe Nemechek NEMCO Toyota +1 lap
32. Juan Pablo Montoya Earnhardt Ganassi Chevolet +6 laps
Denny Hamlin Joe Gibbs Toyota 247 laps
Timmy Hill FAS Lane Ford 225 laps
Dale Earnhardt Jr Hendrick Chevrolet 224 laps
David Reutimann BK Toyota 195 laps
Joey Logano Penske Ford 175 laps
Brian Vickers Waltrip Toyota 161 laps
Cole Whitt Swan Toyota 151 laps
Tony Raines Circle Sport Chevrolet 87 laps
Josh Wise Front Row Ford 84 laps
Reed Sorenson Leavine Ford 68 laps
Michael McDowell Parsons Ford 29 laps