Andretti Autosport’s Colton Herta was the pacesetter on the opening day of testing ahead of next weekend’s Firestone Grand Prix presented by RP Funding in St Petersburg.
Herta set the fastest time in Zebring just ahead of Dale Coyne Racing’s David Malukas and his Andretti team-mate Romain Grosjean.
Josef Newgarden in the No.2 Team Penske Chevrolet was fourth just ahead of his team-mate Will Power in the No.12 Verizon Chevrolet sporting a new livery.
Graham Rahal was sixth in the No.15 United Rentals Honda just ahead of Felix Rosenqvist and Alexander Rossi.
Scott McLaughlin in the No.3 DEX Chevrolet was ninth while Jack Harvey in the No.45 HyVee Honda rounded out the top ten.
Christian Lundgaard was 11th just ahead of Kyle Kirkword and Devlin DeFrancesco while Pato O’Ward was 14th just ahead of Juncos Hollinger Racing’s Callum Ilott.
Tatiana Calderon was 16th in the No.14 ROKiT Chevrolet for AJ Foyt Racing.
Kevin Magnussen rounded out the order for Chip Ganassi Racing. The rest of the field will be action on Tuesday including defending champion Alex Palou.