Ferrari claimed the top two spots on the timesheets on Thursday afternoon in Monaco, as Charles Leclerc and Carlos Sainz finished second practice with time in hand over their rivals.
Mercedes' Lewis Hamilton was almost four tenths off Leclerc's top time, and ended up just 0.007s quicker than Red Bull's Max Verstappen. Valtteri Bottas was fifth fastest ahead of McLaren's Lando Norris.
Yuki Tsunoda damaged the suspension of his AlphaTauri on the barriers and ended up sitting out much of the session having completed just 11 laps, while Mick Schumacher triggered a red flag which brought an early end to the session after hitting the wall at Massenet.
Weather conditions continued to be perfect for Thursday afternoon practice, with air temperature at a very pleasant 22C and no chance of rain. Sadly only a reduced number of fans were in the grandstand able to bask in the sunshine due to ongoing COVID restrictions.
Ferrari's Carlos Sainz was first trying to take advantage of a clear track for an early socially distanced run, but within minutes almost everyone was heading out and Sainz found his first run slightly held up but still good enough for a time of 1:14.997s.
That was quickly bettered by Max Verstappen clocking in at 1:13.961s on the medium compound. His Red Bull team mate Sergio Perez slotting in to second just a tenth behind. Lewis Hamilton's first run saw the world champion cut the Nouvelle chicane, but his next run resulted in a dead heat with Verstappen.
The Red Bull couldn't improve his own time on the next push lap, but Hamilton shaved over a second off and went top with a time of 1:12.772s which he then trimmed by a further two tenths to stay ahead of Verstappen's riposte.
Sainz successfully injected himself into the Mercedes/Red Bull scrap by going second despite being on the hard tyres, and then it was time for everyone to bolt on the soft tyres for true qualifying runs. That allowed Valtteri Bottas to fly ot the top with a time of 1:12.107s while Hamilton once again went awry at the chicane.
Sainz proved that his earlier pace was no fluke and went top with a time of 1:11.796s, which was almost three tenths quicker than Verstappen's bid with Bottas and Hamilton both having laps deleted for exceeding track limits.
Hamilton did find something extra to move ahead of Verstappen but no one could catch Sainz - until his Ferrari team mate Charles Leclerc went quickest with a lap of 1:11.684s with 15 minutes to go, despite missing out on almost all of FP1 with gearbox issues.
Yuki Tsunoda informed the AlphaTauri pit wall that he'd tapped the rear of his car on the Armco and damaged his suspension, forcing to returned to pit lane for the remainder of the session with just 11 laps in the books.
Nicholas Latifi came to a stop at the hairpin to avoid running into the outside barrier, but did eventually got the Williams back underway.
Unfortunately Mick Schumacher was less successful avoiding the wall in the entrance to Massenet. The Haas clattered into the barriers with seven minutes to go; he tried but ultimately failed to limp back to pit lane in 'Punk Mode' but had to park at the run-off after the tunnel exit resulting in the session ending in a red flag
Sebastian Vettel had an unusual issue in the Aston Martin, reporting over the team radio that he had something in his eye: "It feels like my eye is bleeding, I will carry on, but it feels like I am crying."