Ryan Briscoe set the pace in the sole free practice session before qualifying for the IndyCar Series race at Watkins Glen.
The Penske driver, who has not won since the St. Petersburg season opener, hit the front with a 1m29.860s lap with 15 minutes to go, and then shaved another tenth off it to guarantee he would end the morning on top.
Dario Franchitti took second for Ganassi, with Marco Andretti giving Andretti Green a boost by surging to third with his final lap of the session, which pushed Graham Rahal (Newman/Haas/Lanigan) down to fourth. Mario Moraes ended up fifth, but for much of the morning the KV Racing driver had been fastest, only being pushed back during the final runs.
Justin Wilson also took a turn on top, the Dale Coyne Racing driver revelling in the championship's return to road courses, before taking sixth in the end.
Three-time Watkins Glen winner Scott Dixon (Ganassi) was eighth behind AGR's Tony Kanaan and ahead of Helio Castroneves (Penske) and Hideki Mutoh (AGR).
Indy Lights graduate Richard Antinucci took a highly praiseworthy 15th in his first IndyCar session, producing the 3G car's best form of the season so far.
Among the big names he beat were last year's Watkins Glen winner Ryan Hunter-Reay, who was only 16th for A.J. Foyt Racing, and Paul Tracy, who struggled with understeer on his return to KV Racing.
Most of the incidents in the session involved Dreyer & Reinbold drivers. Milka Duno, back this weekend in place of Tomas Scheckter as both drivers are on part-season deals, caused the first stoppage by spinning and stalling at Turn 8 early in the opening half-hour segment for rookies and drivers outside the top 10. Her teammate Mike Conway then prompted the next yellow with a "stupid mistake" at Turn 7, where he spun into the tires and ended his morning after just six laps.
Duno hit further trouble later, parking in the escape road at the Bus Stop chicane having banged wheels with Moraes on the approach to the corner.
HVM's EJ Viso was the only non-D&R driver to have a notable accident -- bringing the session to a close with a spectacular high-speed spin over the curbs on the exit of the Bus Stop.
Pos Driver Team Time Gap
1. Ryan Briscoe Penske 1m29.7715s
2. Dario Franchitti Ganassi 1m29.9424s + 0.1709s
3. Marco Andretti Andretti Green 1m30.0892s + 0.3177s
4. Graham Rahal Newman/Haas/Lanigan 1m30.2503s + 0.4788s
5. Mario Moraes KV 1m30.3020s + 0.5305s
6. Justin Wilson Coyne 1m30.4157s + 0.6442s
7. Tony Kanaan Andretti Green 1m30.4338s + 0.6623s
8. Scott Dixon Ganassi 1m30.4947s + 0.7232s
9. Helio Castroneves Penske 1m30.5572s + 0.7857s
10. Hideki Mutoh Andretti Green 1m30.5979s + 0.8264s
11. Danica Patrick Andretti Green 1m30.6576s + 0.8861s
12. EJ Viso HVM 1m30.8014s + 1.0299s
13. Dan Wheldon Panther 1m30.8392s + 1.0677s
14. Robert Doornbos Newman/Haas/Lanigan 1m31.1722s + 1.4007s
15. Richard Antinucci 3G 1m31.6809s + 1.9094s
16. Ryan Hunter-Reay Foyt 1m31.7804s + 2.0089s
17. Paul Tracy KV 1m32.030s + 2.2588s
18. Mike Conway Dreyer & Reinbold 1m32.3092s + 2.5377s
19. Raphael Matos Luczo Dragon 1m32.3355s + 2.5640s
20. Ed Carpenter Vision 1m32.8942s + 3.1227s
21. Milka Duno Dreyer & Reinbold 1m34.4816s + 4.7101s