Scott Dixon topped third practice for the IndyCar season-opener on the streets of St Peterburg as Honda-powered cars dominated the final session before qualifying.
Ganassi driver Dixon, who was also fastest in Friday's second practice, set the pace with a 1m01.624s lap set midway through the final the session to head James Hinchliffe.
Schmidt Peterson driver Hinchcliffe became the first man to break into the 1m01s so far during the weekend but eventually had to settle for second, 0.042 seconds behind Dixon.
Indianapolis 500 winner Alexander Rossi was third for Andretti, ahead of former F1 driver Max Chilton and late improver Sebastien Bourdais.
Practice one pacesetter Marco Andretti ended the session in sixth place, just under two tenths off four-time champion Dixon's benchmark.
New Penske recruit Josef Newgarden was the first Chevrolet runner on the timesheets in seventh, recording a time less than 0.2s sower than Dixon's, with Ryan Hunter-Reay and Tony Kanaan next up.
Newgarden's Penske team-mates Will Power, Simon Pagenaud and Helio Castroneves finished 10th, 11th and 15th.
Times continued to tumble following Friday's running, although they were still a little way off last year's quickest practice laps due to Turn 3 being reconfigured to make it slower.
Just 1.1 seconds separated the fastest and slowest laps in practice three, set by Dixon and AJ Foyt's Conor Daly - in 21st - respectively.
THIRD PRACTICE TIMES:
|1||Scott Dixon||Chip Ganassi Racing||Dallara/Honda||1m01.6240s||-||18|
|2||James Hinchcliffe||Schmidt Peterson Motorsports||Dallara/Honda||1m01.6660s||0.0420s||22|
|3||Alexander Rossi||Andretti Herta||Dallara/Honda||1m01.7015s||0.0775s||19|
|4||Max Chilton||Chip Ganassi Racing||Dallara/Honda||1m01.7477s||0.1237s||17|
|5||Sebastien Bourdais||Dale Coyne Racing||Dallara/Honda||1m01.7634s||0.1394s||24|
|6||Marco Andretti||Andretti Autosport||Dallara/Honda||1m01.8085s||0.1845s||19|
|7||Josef Newgarden||Team Penske||Dallara/Chevrolet||1m01.8229s||0.1989s||17|
|8||Ryan Hunter-Reay||Andretti Autosport||Dallara/Honda||1m01.8550s||0.2310s||20|
|9||Tony Kanaan||Chip Ganassi Racing||Dallara/Honda||1m01.8562s||0.2322s||22|
|10||Will Power||Team Penske||Dallara/Chevrolet||1m01.9166s||0.2926s||13|
|11||Simon Pagenaud||Team Penske||Dallara/Chevrolet||1m02.0310s||0.4070s||25|
|12||Charlie Kimball||Chip Ganassi Racing||Dallara/Honda||1m02.0345s||0.4105s||20|
|13||Graham Rahal||Rahal Letterman Lanigan||Dallara/Honda||1m02.0793s||0.4553s||27|
|14||Carlos Munoz||AJ Foyt Enterprises||Dallara/Chevrolet||1m02.3289s||0.7049s||21|
|15||Helio Castroneves||Team Penske||Dallara/Chevrolet||1m02.3314s||0.7074s||12|
|16||J.R. Hildebrand||Ed Carpenter Racing||Dallara/Chevrolet||1m02.4174s||0.7934s||22|
|17||Takuma Sato||Andretti Autosport||Dallara/Honda||1m02.4205s||0.7965s||19|
|18||Spencer Pigot||Ed Carpenter Racing||Dallara/Chevrolet||1m02.4207s||0.7967s||24|
|19||Ed Jones||Dale Coyne Racing||Dallara/Honda||1m02.4928s||0.8688s||20|
|20||Mikhail Aleshin||Schmidt Peterson Motorsports||Dallara/Honda||1m02.5968s||0.9728s||22|
|21||Conor Daly||AJ Foyt Enterprises||Dallara/Chevrolet||1m02.7788s||1.1548s||21|