Andrew Benson
BBC Sport’s chief F1 writer

Mercedes, in the words of Red Bull team principal Christian Horner, looked “mighty” on Friday at Imola. But it was a day when comparisons were difficult. Max Verstappen, fastest man if not winner at the first race of the season, lost most of the second session to a driveshaft failure. Mercedes had their engines turned down on the first runs on the fastest ‘soft’ tyre as the engineers did calibration checks.

Ferrari’s Charles Leclerc was the fastest man of the day, but had his best lap time deleted for exceeding track limits by 10cm at Piratella. And Pierre Gasly was hugely impressive in the Alpha Tauri but was gaining 0.5secs on the Mercedes on the straights on his quickest laps, indicating an offset in engine mode.

The takeaways, though, were that Mercedes are very much back, and Horner said Red Bull had “plenty on to give them a hard time”. And Ferrari look set fair to be third fastest team. But that was Friday. Saturday is when it gets serious.

While Max Verstappen, third fastest in session one, only managed 15 minutes of action in session two before a mechanical error ruined his afternoon.

So it was a Mercedes one-two in both sessions yesterday, while other teams had moment they would want to forget.

Ferrari had looked much improved, but the day ended on a sour note as Charles Leclerc went into the wall...

Less than one tenth separated the top three, which means it's all set up for a thrilling qualifying later on.

Image source, F1

Andrew Benson
BBC Sport’s chief F1 writer

Image source, Reuters

Charles Leclerc crashed his Ferrari at the end of what had been an impressive second practice session at the Emilia Romagna Grand Prix.

Leclerc had earlier set the fastest lap time of the session, only to lose it for exceeding track limits. Valtteri Bottas was fastest in the session, just 0.01 seconds quicker than Mercedes team-mate Lewis Hamilton.

Red Bull's Max Verstappen suffered a mechanical failure early in the session.

Bottas' fastest time was set on the mediums, but Hamilton's was on the softs, which is theoretically quicker but on which Mercedes seemed to struggle.

Leclerc's best lap was 0.2secs ahead of Bottas, before it was deleted because he exceeded track limits at Piratella. The Monegasque driver also looked competitive on his race simulation runs.

After his accident in the closing seconds of the session, Leclerc went on the radio to say to his team: "Sorry, guys. I was pushing. Really hard."

Alpha Tauri's Pierre Gasly was third quickest from Ferrari's Carlos Sainz, with Leclerc classified fifth with a lap set later on his soft tyres, when they had lost their edge.

Andrew Benson
BBC Sport’s chief F1 writer

Red Bull’s Sergio Perez and Alpine’s Esteban Ocon collided in first practice at the Emilia Romagna Grand Prix.

The two former team-mates came together at the Villeneuve chicane, causing the session to be stopped for a time. Red Bull team boss Christian Horner said Perez had been on a flying lap and Ocon on a slow lap when they collided.

Mercedes driver Valtteri Bottas was fastest at the end of an incident-packed session that ended with a crash at the Rivazza corner for Haas’s Nikita Mazepin.

The accident continued a torrid start to the Russian’s F1 career. Mazepin had a spin on his very first lap at the same corner at the start of the session, and spun four times at the opening race of the season in Bahrain three weeks ago before crashing out of the race on the first lap.

Hello. Welcome to BBC Sport's coverage of third practice and then qualifying for the Emilia Romagna Grand Prix.

Third practice is at 10:00 BST with qualifying at 13:00 BST and we will have live radio commentary from both.

First up, a quick look back at yesterday's action - and it was a strong day for the reigning champions.