AJ Foyt Racing's Tony Kanaan set the pace on Carb Day, IndyCar's final practice session ahead of the 2018 Indianapolis 500.
Foyt had impressed in qualifying for the race with Kanaan and rookie team-mate Matheus Leist taking 10th and 11th.
In the one-hour session on Friday, Kanaan set a 227.791mph lap that was over 2mph faster than Chip Ganassi Racing's Scott Dixon and his 225.674mph tour in second place.
The session was run in race trim as the field worked on elements including fuel runs, rather than multi-car drafting.
Andretti's Marco Andretti was third ahead of Dale Coyne Racing's Sebastien Bourdais, with the Frenchman starting fifth for Sunday's main event.
Last year's Indy 500 winner Takuma Sato was sixth in a confidence boosting run for Rahal Letterman Lanigan Racing after a challenging Month of May so far, but team-mate Graham Rahal was down in 21st.
Front row starter Will Power was seventh for Penske ahead of Ed Carpenter Racing's Danica Patrick.
Patrick, who has qualified ninth for the race, managed just six laps on Carb Day after an ECU problem forced her to return to the garage.
Her team-mate Spencer Pigot was ninth ahead of Ganassi's Ed Jones and Scuderia Corsa driver Oriol Servia.
Dreyer & Reinbold Racing's Sage Karam topped Monday's practice and finished 12th ahead of the race.
Indy 500 polesitter Ed Carpenter was 14th ahead of Josef Newgarden.
Newgarden's Penske team-mates Helio Castroneves and Simon Pagenaud qualified 17th and 20th respectively.
Andretti full-season driver Zach Veach was 23rd, three places up on Ryan Hunter-Reay.
Alexander Rossi was only 31st ahead of a back row start on Sunday.
Schmidt Peterson Motorsports's Robert Wickens was 27th after crashing out of Monday's practice.