ART Grand Prix's Charles Leclerc recorded the best lap-time on day one of GP3 Series testing at the Red Bull Ring on Tuesday as his morning benchmark of 1m 19.171s remained unbeaten throughout the afternoon.
The Scuderia Ferrari development driver was over half a second quicker than his ART team-mate Nyck de Vries, while another Ferrari protégé, Driver Academy member Antonio Fuoco, posted the fastest lap in the afternoon session, just ahead of Leclerc.
The opening day of the two-day test - designed to help fill the interminable gap between rounds one and two - commenced under hazy blue skies with warm temperatures. Campos Racing's Konstantin Tereshchenko set the early pace ahead of DAMS' Kevin Jorg and Arden International's Jack Aitken.
Jenzer Motorsport's Oscar Tunjo shot to the head of the timesheet after an hour on the clock and was first to dip under 1m 20s, ahead of Trident driver Fuoco and Leclerc. However, there was a short red flag period after the Colombian brushed the barrier while holding down P1.
Leclerc found some extra pace to join Tunjo in the 1m19s, going second overall ahead of de Vries in the second half of the morning session. In the final 15 minutes, there were a flurry of changes, with the ART Grand Prix quartet on the move and swapping positions every lap. Monegasque rookie Leclerc eventually set a flier to nail down P1, half a second quicker than his Dutch team-mate with Alexander Albon in third.
The positions remained the same at the chequered flag, with Tunjo fourth ahead of Jake Hughes, Nirei Fukuzumi, Fuoco, Aitken, Matthew Parry and Sandy Stuvik.
Following a one-hour break, Parry was the initial afternoon pace-setter, ahead of Hughes and Fukuzumi, until the Japanese rookie moved to the top of the timesheet by posting a 1m 20.210s lap at the mid-point of the session.
There was a brief stoppage when Steijn Schothorst stopped on track but, once the action resumed, Leclerc returned to the head of the timings when he was first to lap in the 1m 19s, going two-tenths faster than his team-mate. Fuoco bettered his time by 0.09s soon after to grab P1 with 45 minutes remaining, before another red flag period interrupted proceedings as Calderon and Tunjo both stopped on track.
Hughes moved up to third as the clock ticked down, only for de Vries to demote him but, at the chequered flag, Fuoco remained on top, ahead of Leclerc, de Vries, Hughes, Parry, Fukuzumi, Albon, Richard Gonda, Artur Janosz and Ralph Boschung.