Lewis Hamilton led a 1-2 for the Mercedes Formula 1 team in the opening practice session for the Austrian Grand Prix.
Verstappen was the first driver to set a laptime and became an early session spinner when he ran wide exiting Turn 4, dipping his left-side wheels into the gravel and performing a neat 360-degree spin in his Red Bull before continuing.
When the serious running kicked off on supersofts, Mercedes was quick to the hit the front, with Bottas and Hamilton first into the 1m05s and Hamilton assuming control on a 1m05.525s at mid-distance.
Bottas emerged on ultrasofts just before his teammate and reclaimed P1 on a 1m05.354s, but Hamilton hit back immediately with a time three tenths faster.
Vettel then split the Mercedes in his Ferrari and traded P2 with Bottas over a succession of laps before Verstappen set a 1m05.072s on fresh ultrasofts to slot in just 0.045s behind Hamilton.
Mercedes' 1-2 was soon re-established though, as both drivers dipped below the 1m05s-mark – Hamilton on a 1m04.839s and Bottas just over a tenth back.
That remained the lead order, with Verstappen's best enough to keep him a tenth clear of Vettel in the best of the Ferraris.
Daniel Ricciardo beat the second Ferrari of Kimi Raikkonen, but was four tenths down on his teammate Verstappen.
Ricciardo had been rapid on the early runs, using soft tyres as others used supersofts and ultrasofts, but then spent quite a lot of time in the garage after checking for damage following a big kerb hit.
He improved but did not make massive progress when he emerged on Pirelli's softest rubber and stayed fifth, three tenths clear of Raikkonen.
Romain Grosjean earned initial best-of-the-rest honours for Haas in seventh, 0.027s faster than Force India's Esteban Ocon, with both drivers only using supersoft tyres.
Sauber's strong form continued with Charles Leclerc ninth, on ultrasofts, while Toro Rosso driver Pierre Gasly completed the top 10 on supersofts.
Gasly lost a piece of his Toro Rosso's front wing running wide at the fast penultimate corner.
Stoffel Vandoorne damaged his McLaren more significantly, breaking the tip of his nose when he took to the run-off between the two right-handers that end the lap.
Vandoorne wound up 18th, one place behind teammate Fernando Alonso, as McLaren steered clear of the ultrasoft tyre.
The Belgian is under investigation for an unsafe release after Vettel nearly made contact with he McLaren as it entered the pitlane.
McLaren was the slowest team and its drivers were faster only than Toro Rosso's Brendon Hartley and Williams reserve Robert Kubica, who was slowest of all and 0.9s behind teammate Lance Stroll as he replaced Sergey Sirotkin for opening practice.
|3||Max Verstappen||Red Bull||TAG||42||1'05.072||0.233|
|5||Daniel Ricciardo||Red Bull||TAG||22||1'05.483||0.644|
|8||Esteban Ocon||Force India||Mercedes||40||1'06.055||1.216|
|10||Pierre Gasly||Toro Rosso||Honda||36||1'06.394||1.555|
|14||Sergio Perez||Force India||Mercedes||42||1'06.455||1.616|
|19||Brendon Hartley||Toro Rosso||Honda||45||1'06.871||2.032|