Justin Wilson set the pace in the final practice session for the latest round of the IndyCar Series at Mid-Ohio.
The Dale Coyne Racing driver vied with his British compatriot Dario Franchitti as well as Scott Dixon, before he went to the top of the timesheets definitively after 20 minutes with a time of 1m07.478 - almost three quarters of a second quicker than Dixon's pace-setting time from Friday practice.
The onset of rain with 20 minutes of the hour-long session remaining prevented either of the Ganassi drivers from knocking Wilson off the top spot, Franchitti winding up second quickest - 0.2 seconds behind.
Around a third of the field returned to the track after the rain began to fall, each driver attempting to scrub-in a set of wet tyres as a precaution in case either qualifying or the race takes place in similar conditions.
Championship leader Ryan Briscoe was third quickest in the best of the Penske cars, with Graham Rahal (Newman/Haas/Lanigan Racing) fourth.
Marco Andretti was the quickest of the Andretti-Green drivers in fifth, one spot ahead of the hugely impressive Raphael Matos (Luczo Dragon) and two ahead of Dixon, who slipped down the order as he sat in the pits in order to save a set of slicks for later.
Oriol Servia, who is returning to the series with NHLR following Robert Doornbos's switch to HVM, continued his re-acclimatisation in ninth.
It was a bad session for 2003 and 2005 series champions Tony Kanaan and Dan Wheldon. Kanaan (AGR) hit the barriers at the final corner after half an hour, damaging his nosecone, while Wheldon (Panther Racing) spun on slicks just as the rain began to fall.
Even worse befell Paul Tracy, a late call-up by KV Racing to replace Mario Moraes. Tracy ran wide exiting Turn Five on his out-lap and then spun across the circuit before stalling his engine on the grass. He then repeated the excursion, albeit without the stall, as the rain began to fall.
Pos Driver Team Time Gap
1. Justin Wilson Coyne 1m07.4779s
2. Dario Franchitti Ganassi 1m07.6888s + 0.2109s
3. Ryan Briscoe Penske 1m07.6974s + 0.2195s
4. Graham Rahal Newman/Haas/Lanigan 1m07.9796s + 0.5017s
5. Marco Andretti Andretti Green 1m08.1374s + 0.6595s
6. Raphael Matos Luczo Dragon 1m08.2475s + 0.7696s
7. Scott Dixon Ganassi 1m08.3422s + 0.8643s
8. Helio Castroneves Penske 1m08.3590s + 0.8811s
9. Oriol Servia Newman/Haas/Lanigan 1m08.4617s + 0.9838s
10. Ryan Hunter-Reay Foyt 1m08.4686s + 0.9907s
11. Hideki Mutoh Andretti Green 1m08.5195s + 1.0416s
12. Tony Kanaan Andretti Green 1m08.6661s + 1.1882s
13. Dan Wheldon Panther 1m09.0909s + 1.6130s
14. EJ Viso HVM 1m09.0931s + 1.6152s
15. Danica Patrick Andretti Green 1m09.2663s + 1.7884s
16. Paul Tracy KV 1m09.5176s + 2.0397s
17. Ed Carpenter Vision 1m09.5423s + 2.0644s
18. Richard Antinucci 3G 1m09.6445s + 2.1666s
19. Robert Doornbos HVM 1m09.8583s + 2.3804s
20. Mike Conway Dreyer & Reinbold 1m10.4172s + 2.9393s
21. Milka Duno Dreyer & Reinbold 1m13.9824s + 6.5045s