Max Verstappen, who faces a 10-place grid penalty for Sunday's race, topped the times for Red Bull ahead of McLaren's Oscar Piastri in Friday's opening free practice at this weekend's Belgian Grand Prix.

Five days after his sweary outbursts on team radio at the Hungaroring, the series leader and three-time world champion did his talking on the track by outpacing Piastri, who claimed his maiden Formula One victory in Hungary, by 0.531 seconds.

Verstappen clocked a best lap in one minute and 43.372 seconds and remained unchallenged at the front of the field throughout the session as he began his bid to end a three-race winless run by claiming his fourth consecutive Belgian triumph.

Williams' Alex Albon was third fastest, ahead of the Mercedes of George Russell and seven-time champion Lewis Hamilton, Ferrari's Charles Leclerc, Sergio Perez of Red Bull and Lando Norris in the second McLaren.

Carlos Sainz was ninth for Ferrari and Lance Stroll 10th for Aston Martin.

On a warm, if cloudy, summer's day following an earlier rain shower in the Ardennes, Russell was the first man out, but it was Verstappen who set the first top time on hard tyres in 1:44.706, Piastri soon clocking into second place, seven-tenths adrift of the Dutchman.

Norris, both Ferrari drivers and Hamilton, like the Australian, were initially on softs while Esteban Ocon, fresh from announcing his switch to Haas next year, was stuck in the Alpine garage as the team worked on a suspected water leak.

As Verstappen began to trim his time, his 10-place grid penalty for taking a fresh engine was confirmed along with one for RB's Yuki Tsunoda who will start from the back of the grid after taking more power unit components.

By midway through the session, Perez had joined Verstappen on track and switched to softs, taking fifth place, but complained that his car was unresponsive. "I'm really struggling to know what the car is doing on entries," he reported.

At this stage, Verstappen topped the times ahead of Piastri and Alex Albon, whose Williams was showing real potential, and the two Mercedes of Russell and Hamilton, with Leclerc sixth ahead of Perez.

With nine minutes remaining, and most drivers on softs after running qualifying simulation laps, Hamilton ran wide at Les Combes before pitting. "I've got to come in," he said. "The bouncing is really bad."

Russell had complained only minutes earlier that he had 'no rear end', but the drivers' grumbles failed to hid the fact that they had shown inconsistent pace in the opening session run in conditions more suited to their package.