Castroneves beats Dixon in practice

Ganassi driver Dixon, who leads Castroneves by 43 points with 104 up for grabs in the two remaining championship rounds, topped the morning session on a still-dirty track by a comfortable half a second.

But in the improved conditions of the afternoon, Castroneves (Penske) turned the tables on Dixon in the closing stages - setting a 1:13.2059 lap to end the day on top by 0.4937 seconds.

"We are headed in a good direction, but we are going to have to keep working," said Castroneves.

Although Dixon was underwhelmed by his day, he was confident that his car had the potential to go faster tomorrow.

"I had a problem with hitting the wall twice and bent the tow link," he said. "We actually had to repair the car in the middle of the session and had to end early because we had to fix it.

"The car was actually quick out of the box. I think we were quickest in the first 10 minutes, but we had a lot of understeer. We tried dialing it out and made the car a lot worse.

"We put a set of stickers (new tyres) on the car and it was pretty average. I think the car can be a little bit quicker, and using the baseline set-up from this morning, it should have been quicker. Helio is quite fast, but I don't know if the track changed because of the weather."

Panther Racing's Vitor Meira was third in second practice, pushing Castroneves' Penske teammate Ryan Briscoe down to fourth.

Andretti Green duo Danica Patrick and Tony Kanaan completed the top six, but their teammate Marco Andretti struggled - languishing in 20th in the morning and only improving to 18th later on.

Behind seventh-placed Ryan Hunter-Reay (Rahal Letterman), Darren Manning and Bruno Junqueira impressed by taking eighth and 10th for their respective underdog teams Foyt and Dale Coyne, while KV Racing duo Oriol Servia and Will Power rebounded to take ninth and 11th in second practice having both lost wheels in the morning.

The KV cars' unusual problems aside, the day passed with little incident bar a number of spins for struggling owner/driver Marty Roth.

Practice one:

Pos  Driver             Team                 Time
 1.  Scott Dixon        Ganassi              1:13.9714
 2.  Helio Castroneves  Penske               1:14.4954  + 0.5240
 3.  Ryan Briscoe       Penske               1:14.9002  + 0.9288
 4.  Tony Kanaan        Andretti Green       1:15.6494  + 1.6780
 5.  Ryan Hunter-Reay   Rahal Letterman      1:15.7004  + 1.7290
 6.  Danica Patrick     Andretti Green       1:15.7323  + 1.7609
 7.  Graham Rahal       Newman Haas Lanigan  1:15.9390  + 1.9676
 8.  Dan Wheldon        Ganassi              1:15.9760  + 2.0046
 9.  Darren Manning     Foyt                 1:16.0432  + 2.0718
10.  Vitor Meira        Panther              1:16.0602  + 2.0888
11.  Ernesto Viso       HVM                  1:16.2482  + 2.2768
12.  Hideki Mutoh       Andretti Green       1:16.4874  + 2.5160
13.  AJ Foyt IV         Vision               1:16.7216  + 2.7502
14.  Will Power         KV                   1:16.7979  + 2.8265
15.  Tomas Scheckter    Luczo Dragon         1:16.8601  + 2.8887
16.  Bruno Junqueira    Dale Coyne           1:16.9212  + 2.9498
17.  Oriol Servia       KV                   1:17.2074  + 3.2360
18.  Mario Moraes       Dale Coyne           1:17.3831  + 3.4117
19.  Buddy Rice         Dreyer & Reinbold    1:17.4258  + 3.4544
20.  Marco Andretti     Andretti Green       1:17.6144  + 3.6430
21.  Justin Wilson      Newman Haas Lanigan  1:17.9563  + 3.9849
22.  Ed Carpenter       Vision               1:18.3216  + 4.3502
23.  Jaime Camara       Conquest             1:19.4043  + 5.4329
24.  Enrique Bernoldi   Conquest             1:19.4495  + 5.4781
25.  Milka Duno         Dreyer & Reinbold    1:23.5300  + 9.5586
26.  Marty Roth         Roth                 1:33.5782  + 19.6068

Practice two:

Pos  Driver             Team                 Time
 1.  Helio Castroneves  Penske               1:13.2059
 2.  Scott Dixon        Ganassi              1:13.6996  + 0.4937
 3.  Vitor Meira        Panther              1:13.9816  + 0.7757
 4.  Ryan Briscoe       Penske               1:14.1373  + 0.9314
 5.  Danica Patrick     Andretti Green       1:14.4452  + 1.2393
 6.  Tony Kanaan        Andretti Green       1:14.6517  + 1.4458
 7.  Ryan Hunter-Reay   Rahal Letterman      1:14.6552  + 1.4493
 8.  Darren Manning     Foyt                 1:14.7119  + 1.5060
 9.  Oriol Servia       KV                   1:14.7147  + 1.5088
10.  Bruno Junqueira    Dale Coyne           1:14.7326  + 1.5267
11.  Will Power         KV                   1:14.8398  + 1.6339
12.  Tomas Scheckter    Luczo Dragon         1:14.8960  + 1.6901
13.  Justin Wilson      Newman/Haas/Lanigan  1:14.9100  + 1.7041
14.  Graham Rahal       Newman/Haas/Lanigan  1:14.9609  + 1.7550
15.  EJ Viso            HVM                  1:15.0732  + 1.8673
16.  Dan Wheldon        Ganassi              1:15.2644  + 2.0585
17.  Hideki Mutoh       Andretti Green       1:15.5606  + 2.3547
18.  Marco Andretti     Andretti Green       1:15.5702  + 2.3643
19.  Ed Carpenter       Vision               1:16.2213  + 3.0154
20.  Mario Moraes       Dale Coyne           1:16.4200  + 3.2141
21.  Buddy Rice         Dreyer & Reinbold    1:16.6437  + 3.4378
22.  AJ Foyt IV         Vision               1:16.7840  + 3.5781
23.  Jaime Camara       Conquest             1:17.2781  + 4.0722
24.  Enrique Bernoldi   Conquest             1:18.0948  + 4.8889
25.  Milka Duno         Dreyer & Reinbold    1:20.6361  + 7.4302
26.  Marty Roth         Roth                 1:25.0063  + 11.8004