McLaren have traced the engine failure in last weekend’s Dutch Grand Prix that dented Norris’ title hopes to a broken oil line – a McLaren issue rather than a problem with the Mercedes engine.
Leclerc’s fastest time was his third attempt to do a lap on the soft tyres after aborting his first two runs.
The second incident led to a scare because Leclerc passed a Sauber just after a red flag was thrown because of gravel on track, despite braking as hard as he could.
He was worried he would receive a penalty, but stewards immediately reviewed the incident and accepted there was nothing he could do.
Verstappen was 0.575secs off Hamilton, while the second Williams of Alex Albon was seventh.
A number of drivers ran wide during the session, and the red flag was as a result of Racing Bulls’ Isack Hadjar running off track at the Ascari chicane and spraying the circuit with gravel.
Gravel at the second Lesmo, deposited by Norris, also needed to be cleared.
Other drivers to run wide and kick up gravel included Aston Martin’s Fernando Alonso, who was ninth fastest behind George Russell’s Mercedes.
Russell ended the session parked on the grass beside the track before the Roggia chicane as a result of a power loss, which left him stuck in seventh gear with the rear wheels locked.
Hadjar completed the top 10.
