Jamie Whincup fended off Triple 8 Holden team-mate Craig Lowndes to win V8 Supercars' maiden American race at Austin.
Whincup beat slow-starting polesitter Fabian Coulthard to the first corner and proceeded to pull away in the opening laps as Coulthard held up Lowndes.
It took six laps before Lowndes managed to battle past Coulthard, by which time Whincup was nearly three seconds clear.
But running five laps longer before his pitstop allowed Lowndes to rejoin right on Whincup's tail.
He put his champion team-mate under huge pressure for many laps before Whincup got a little breathing space, managing to win by 0.9 seconds after a final-lap slide by Lowndes.
The latter's second place could yet come under threat as the stewards are investigating whether he spun his wheels during his pitstop.
Coulthard became embroiled in a spectacular dice with Jonathon Webb and Will Davison for the rest of the first stint.
The pitstops split this pack up, and Coulthard was left in a clear third for Brad Jones Racing.
Davison came home fourth, followed by Garth Tander, Rick Kelly's Nissan and Webb, who was delayed by pitlane traffic when trying to exit his stop.
Mark Winterbottom skittered off the road at Turn 1 late on while fighting with Webb and fell to eighth, ahead of Tander's Holden Racing Team partner James Courtney.
David Wall had qualified a breakthrough fourth for Britek, but drifted down to 10th in the race.
Coulthard's team-mate Jason Bright waited until the final lap to make his pitstop having struggled in qualifying, a strategy that put him in the lead for a long spell and salvaged a 12th-place finish.
Adelaide winner Shane van Gisbergen was thrown out of qualifying for a parc ferme infringement. His race charge was rapidly stymied by a misfire.
Results - 27 laps: Pos Driver Team/Car Time/Gap 1. Jamie Whincup Triple 8 Holden 44m20.8482s 2. Craig Lowndes Triple 8 Holden + 0.9030s 3. Fabian Coulthard Brad Jones Holden + 8.6280s 4. Will Davison FPR Ford + 12.6896s 5. Garth Tander HRT Holden + 14.3523s 6. Rick Kelly Nissan + 15.5188s 7. Jonathon Webb Tekno Holden + 16.3815s 8. Mark Winterbottom FPR Ford + 19.3333s 9. James Courtney HRT Holden + 21.3329s 10. David Wall Britek/BJR Holden + 25.9052s 11. David Reynolds Rod Nash/FPR Ford + 26.9481s 12. Jason Bright Brad Jones Holden + 33.6108s 13. Chaz Mostert Dick Johnson Ford + 34.2852s 14. Alex Davison Schwerkolt/FPR Ford + 39.8091s 15. Scott Pye GRM Holden + 40.4631s 16. James Moffat Nissan + 40.4929s 17. Alexandre Premat GRM Holden + 41.7636s 18. Tony D'Alberto D'Alberto Holden + 42.5892s 19. Tim Blanchard Dick Johnson Ford + 43.0022s 20. Michael Caruso Nissan + 43.0457s 21. Dean Fiore Dumbrell Holden + 48.1767s 22. Tim Slade Rosenberg/Erebus Mercedes + 48.6056s 23. Maro Engel Erebus Mercedes + 50.7014s 24. Russell Ingall Walkinshaw/HRT Holden + 1m00.0065s 25. Todd Kelly Nissan + 1m18.2760s 26. Shane van Gisbergen Tekno Holden + 2 laps 27. Lee Holdsworth Erebus Mercedes + 3 laps 28. Scott McLaughlin GRM Holden + 4 laps