Red Bull's Max Verstappen topped the timesheet at the end of the first day of Barcelona's in-season test, just edging out Renault's Carlos Sainz by 0.034s.
The Dutch driver put 148 laps under his belt on Tuesday, using Pirelli's supersoft tyre to record a best time of 1m17.528s in the last sixty minutes of the afternoon session.
Sainz put his Renault-shod hypersoft just ahead of Sebastian Vettel's Ferrari, while Romain Grosjean, the morning's pace-setter, finished his day on fourth.
It was a drama-free afternoon of running for most competitors, including rookie Nicholas Latifi, who clocked in P5 for Force India, knocking Mercedes' Lewis Hamilton down to sixth, the Spanish Grand Prix winner achieving the biggest lap tally for the day with 151 laps.
McLaren's Stoffel Vandoorne concluded his day 7th, ahead of Saubers' Antonio Giovinazzi.
Williams apprentice Oliver Rowland made progress compared to his morning performance, completing 100 laps on the day.
Both Lando Norris and Georges Rusell had their work cut out for them by Pirelli, running respectively in McLaren and Force India's second cars.
Sean Geleal for Toro Rosso and Oliver Turvey for McLaren rounded off the 13-strong field.