Red Bull junior Juri Vips was fastest in Formula 2 practice at Mugello, edging series veteran Luca Ghiotto by just 0.089 seconds.
20-year-old Vips is competing in his third weekend in F2 with DAMS, deputising for the injured Sean Gelael.
Travel restrictions meant Vips was unable to participate in Super Formula's season-opening Twin Ring Motegi double-header round with Team Mugen as originally planned.
Vips then elected to run in the Formula Regional European Championship with Finnish squad KIC Motorsport to try and obtain the remaining required FIA Formula 1 superlicence qualification points.
However, he has now chosen to prioritise F2 at Mugello over the clashing third FREC round of the season at the Red Bull Ring.
Vips is yet to score a point in the championship after placing one position out of the points in each of his first four races.
He topped practice with a 1m31.474s, just ahead of Hitech GP's Luca Ghiotto. MP Motorsport's Felipe Drugovich rounded out the top three.
Red Bull and Honda protege Yuki Tsunoda was fourth fastest ahead of ex-Red Bull junior Dan Ticktum, who lost his second sprint race victory of the year last Sunday at Spa after failing to provide an adequate fuel sample.
Trident's Marino Sato has finished no higher than 13th place this year, but recorded the sixth quickest time of the 45-minute session.
Williams F1 reserve driver Jack Aitken finished the session with the seventh-fastest time but crashed at the final corner with around 10 minutes to go.
Campos Racing's Aitken locked up, slid through the gravel and ended up in the wall at the final sweeping corner.
Hitech's Nikita Mazepin, Renault junior Christian Lundgaard (ART Grand Prix) and Trident's Roy Nissany rounded out the top 10.
Haas F1 reserve driver Louis Deletraz was 11th ahead of Prema's Ferrari juniors Mick Schumacher and Robert Shwartzman.
Championship leader Callum Ilott (UNI-Virtuosi) and his Ferrari stablemate Marcus Armstrong (ART) completed the top 15.
HWA Racelab's Jake Hughes edged Trident's Lirim Zendeli by just 0.008s in FIA Formula 3 practice as the final round of the season commenced.
Six drivers are in mathematical contention for the title with Renault junior Oscar Piastri currently enjoying an eight-point advantage over his Prema team-mate Logan Sargeant at the top of the drivers' championship.
Both drivers will serve grid penalties for causing incidents at last weekend's Monza round, with Piastri set to drop five places on the grid while Sargeant will drop three spots.
Sargeant placed eighth in practice and Piastri could only manage the 13th fastest time.
Their nearest championship rival Theo Pourchaire, who sits 24 points adrift of Piastri, was fifth quickest in practice for ART Grand Prix.
F2 Mugello practice results
|2||Luca Ghiotto||Hitech Grand Prix||1m31.563s||0.089s|
|3||Felipe Drugovich||MP Motorsport||1m31.705s||0.231s|
|7||Jack Aitken||Campos Racing||1m32.061s||0.587s|
|8||Nikita Mazepin||Hitech Grand Prix||1m32.097s||0.623s|
|9||Christian Lundgaard||ART Grand Prix||1m32.101s||0.627s|
|11||Louis Deletraz||Charouz Racing System||1m32.296s||0.822s|
|12||Mick Schumacher||Prema Racing||1m32.331s||0.857s|
|13||Robert Shwartzman||Prema Racing||1m32.408s||0.934s|
|15||Marcus Armstrong||ART Grand Prix||1m32.451s||0.977s|
|16||Pedro Piquet||Charouz Racing System||1m32.608s||1.134s|
|18||Artem Markelov||BWT HWA RACELAB||1m33.010s||1.536s|
|20||Giuliano Alesi||BWT HWA RACELAB||1m33.143s||1.669s|
|21||Nobuharu Matsushita||MP Motorsport||1m33.695s||2.221s|
|22||Guilherme Samaia||Campos Racing||1m34.021s||2.547s|