Six-time IndyCar champion Scott Dixon led his Chip Ganassi Racing team-mates in the opening test of 2021 at Sebring International Raceway.
The 40-year-old reigning champion, who has 50 IndyCar wins to his name, lapped the 1.7-mile course in 52.320 seconds, one-tenth faster than former Formula 1 star Marcus Ericsson who is about to embark on his third IndyCar season and his second with the Ganassi team.
Just seven drivers were in action on the opening day of 2021 IndyCar testing at Sebring, with a host of contenders set to join the action on Tuesday.
Less than half a tenth behind them was one of the team's new recruits, series sophomore Alex Palou, who had previously tested with the squad at Barber Motorsports Park and Laguna Seca.
A.J. Foyt Racing's Sebastien Bourdais, who ended last season on an upbeat note with fourth place at St. Petersburg and this year becomes a full-timer, was a little more than a quarter of a second off Dixon's pace.
His team-mate Dalton Kellett is was a further three-tenths in arrears, the pair separated by Max Chilton in the Carlin.
Seven-time NASCAR champion Jimmie Johnson turned more laps than anyone else as he continues his brave effort to adapt to open-wheel racing and he ended the day just under 1.4s off team-mate Dixon's pace.
Tuesday will see Ryan Hunter-Reay, Alexander Rossi, Marco Andretti and Colton Herta joining the action for Andretti Autosport, with Graham Rahal and Takuma Sato testing for Rahal Letterman Lanigan, and Jack Harvey in the cockpit for Meyer Shank Racing.
2021 IndyCar testing - Sebring Day 1
1. Scott Dixon Chip Ganassi Racing 52.320s 109 laps
2. Marcus Ericsson Chip Ganassi Racing 52.417s 127 laps
3. Alex Palou Chip Ganassi Racing 52.455s 121 laps
4. Sebastien Bourdais A.J. Foyt Enterprises 52.589s 116 laps
5. Max Chilton Carlin 52.890s 139 laps
6. Dalton Kellett AJ Foyt Enterprises 52.962s 135 laps
7. Jimmie Johnson Chip Ganassi Racing 53.691s 160 laps