While Russell led the way for Mercedes following the opening laps, the session was brought to a brief halt 20 minutes in when Alex Albon – whose new multi-year contract extension with Williams was announced this week – pulled off track due to a mechanical issue.
As many bolted on the soft compound tyres for some fast laps after the action resumed, Leclerc went quickest at the halfway point for Ferrari with a time of 1m 17.438s.
Elsewhere several drivers experienced wide moments in the windy conditions, while Lewis Hamilton suffered a spin but managed to return his Mercedes to the track.
NEED TO KNOW: The most important facts, stats and trivia ahead of the Emilia Romagna Grand Prix
It was Leclerc who was on top at the end of the hour on a lap of 1m 16.990s in the upgraded SF-24, followed by Russell in the Mercedes a further 0.104s behind, with Sainz in the other of the Scuderia’s cars in third.
Sergio Perez was the lead Red Bull in P4, while team mate Max Verstappen – who complained about a lack of grip and had more than one excursion across the grass in his final laps – went P5. RB’s Yuki Tsunoda followed in P6, ahead of Hamilton in P7 and Miami winner Lando Norris in P8 for McLaren.
