Ryan Briscoe edged out Helio Castroneves to top the timing screens in a windy third IndyCar practice session at St Petersburg.
The Australian, who moved to Ganassi during the off-season, bumped Castroneves from the top spot with a 1m02.4236s lap three minutes before the session ended.
There was not much in it though, with the top two separated by just 0.04s, and the top 12 covered by 0.5s.
"The conditions were tough out there," said Briscoe. "The wind is so strong, and it is blowing in different directions to yesterday. To be honest the car didn't feel that great, but I guess everyone is struggling out there.
"We made a lot of changes during the session and none of them really helped, so at the end we just went back to our starting set-up."
The track had also been rinsed clean by overnight rain, although Briscoe admitted that it hadn't made a lot of difference.
"To be honest, the track never really rubbered in yesterday," he said.
Takuma Sato's solid start to the weekend continued with the AJ Foyt driver finishing up third fastest ahead of early session leader Sebastien Bourdais, both of whom late late improvements to their times to knock Will Power down to fifth.
Ganassi's lead duo of Tony Kanaan and Scott Dixon continued to play themselves into the weekend quietly, finishing the morning eighth- and ninth-fastest respectively, putting them just ahead of quickest rookie Jack Hawksworth.
Pos Driver Team Time Gap Laps 1. Ryan Briscoe Ganassi/Chevy 1m02.4236s 18 2. Helio Castroneves Penske/Chevy 1m02.4730s + 0.0494s 23 3. Takuma Sato Foyt/Honda 1m02.5243s + 0.1007s 20 4. Sebastien Bourdais KV/Chevy 1m02.5445s + 0.1209s 23 5. Will Power Penske/Chevy 1m02.5996s + 0.1760s 20 6. Simon Pagenaud Schmidt/Honda 1m02.6632s + 0.2396s 22 7. James Hinchcliffe Andretti/Honda 1m02.7352s + 0.3116s 22 8. Tony Kanaan Ganassi/Chevy 1m02.7450s + 0.3214s 19 9. Scott Dixon Ganassi/Chevy 1m02.7910s + 0.3674s 17 10. Jack Hawksworth Herta/Honda 1m02.7951s + 0.3715s 19 11. Ryan Hunter-Reay Andretti/Honda 1m02.7976s + 0.3740s 20 12. Mikhail Aleshin Schmidt/Honda 1m02.8409s + 0.4173s 24 13. Justin Wilson Coyne/Honda 1m02.9237s + 0.5001s 18 14. Graham Rahal Rahal/Honda 1m02.9266s + 0.5030s 23 15. Juan Pablo Montoya Penske/Chevy 1m03.0008s + 0.5772s 19 16. Carlos Munoz Andretti/Honda 1m03.0537s + 0.6301s 25 17. Josef Newgarden Fisher/Honda 1m03.1279s + 0.7043s 17 18. Charlie Kimball Ganassi/Chevy 1m03.1492s + 0.7256s 22 19. Mike Conway Carpenter/Chevy 1m03.2338s + 0.8102s 24 20. Marco Andretti Andretti/Honda 1m03.3061s + 0.8825s 15 21. Sebastian Saavedra KV/Chevy 1m03.3738s + 0.9502s 23 22. Carlos Huertas Coyne/Honda 1m03.7357s + 1.3121s 19