Charles Leclerc unleashed the pace many had been expecting from Ferrari at the Monaco Grand Prix to top second practice at his home race.
Having opted not to use soft tyres as Lewis Hamilton led the opening session earlier on Friday, Leclerc was in a league of his own when finally given the chance to use the quickest compound at the street circuit.
Hamilton completed an encouraging day for Mercedes by taking second, eventually closing the gap to Leclerc to within two tenths as the seven-time world champion took advantage of the constantly evolving surface.
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Despite improving on the 11th place he took in first practice, world championship leader Max Verstappen continued to struggle with the handling of his Red Bull and finished fourth, more than half a second back from Leclerc.
Fernando Alonso, who was narrowly beaten to pole by Verstappen in Monaco last year, used his vast experience to take an encouraging third for Aston Martin.
Lando Norris was fifth for McLaren but didn't use a new set of soft tyres during the session, while Leclerc's Ferrari team-mate Carlos Sainz was sixth.
Red Bull's struggles were further highlighted by Sergio Perez only managing eighth, with the Mexican joining Verstappen in complaining over the handling of the RB20 over team radio.
As had been the case in first practice, George Russell was way off the pace of his Mercedes team-mate Hamilton and continued to complain of heavy vibrations as he finished 10th.
While nobody will count out Verstappen after he turned around a similarly bleak Friday in Imola last weekend to take pole and a race victory, there is no doubt that the Dutchman faces a huge challenge to claim a record ninth successive pole.
A final hour of practice comes first thing on Saturday, but the ease with which he shot to the top of the timesheet on Friday afternoon ensures Leclerc will enter the weekend as favourite for a qualifying session that usually also decides Sunday's race winner.
Red Bull's Monaco display leaves Verstappen with headache
Red Bull had a metaphorical headache after a poor Friday in Imola last weekend, but this time the performance of the RB20 left Verstappen complaining of an actual headache.
The kerbs and bumpy nature of the famous street circuit create a rare track that does not suit Red Bull's all-conquering car, and that was evident on Friday.
While just about every driver must have brushed several barriers during the day's two sessions, Verstappen produced one of the day's heaviest collisions as the left side of his car slid into the wall at Turn 7.
He returned to the pits after the incident and thankfully, with no major damage, was able to return to the track almost immediately.
After the let-off, he was able to do his first soft-tyre running of the day but was more than two tenths of a second off Leclerc's strongest lap on the medium tyre.
Just moments later, with the track therefore at the same level of evolution, Leclerc used his first set of soft tyres to improve his best medium time by almost three further tenths, emphasising his advantage over Verstappen.
With the Ferrari appearing to be working very well, all eyes will be on Leclerc on Saturday as he looks to give himself the best possible chance of ending the 'curse' at his home circuit that has denied him a podium finish in every appearance at the track during his motorsport career.
Hamilton impresses as Norris goes under radar
Hamilton topping the opening session had been quite the surprise, but the fact that neither Red Bull nor Ferrari had run soft tyres ensured the result was noted with caution.
However, the fact that Hamilton was Leclerc's nearest challenger later in the day suggests that the Silver Arrows are carrying competitive one-lap speed.
The team's poor start to the season led Hamilton to say during his press briefing on Thursday that learning Italian ahead of his move to Ferrari next year will be easier than Mercedes securing a podium, but the 39-year-old will now surely be sniffing an upset.
Hamilton's performance enabled him to steal some of the limelight back from fellow Brit Norris, whose profile has risen since a maiden F1 victory in Miami earlier this month.
Having finished second to Verstappen in races either side of his Miami win, Norris came into the weekend with hopes he could challenge the Dutchman, or Ferrari, for victory once more.
Norris was only fourth in the first session, behind both Mercedes cars and his team-mate Oscar Piastri, but the fact he didn't use new soft tyres in second practice made his afternoon pace difficult to assess.
Much like with Verstappen and Red Bull, it would be dangerous to rule out Norris given his recent form, while the same could be said for Piastri, who has regularly been a match for his team-mate in qualifying.
Sky Sports F1's live Monaco GP and Indy 500 schedule
Saturday May 25
9.40am: F3 Sprint
11.15am: Monaco GP Practice Three (session starts at 11.30am)*
1.10pm: F2 Sprint*
2.15pm: Monaco GP Qualifying build-up*
3pm: Monaco GP Qualifying*
5pm: Ted's Qualifying Notebook
Sunday May 26
6.55am: F3 Feature Race
8.35am: F2 Feature Race
12.30pm: Grand Prix Sunday: Monaco GP build-up*
2pm: The MONACO GRAND PRIX*
4pm: Chequered Flag: Monaco GP reaction
5pm: Ted's Notebook
5.30pm: The Indy 500
*also live on Sky Sports Main Event
It's time for the most-famous F1 race of them all - the Monaco Grand Prix. Watch every session from the famous street circuit live on Sky Sports F1, with Sunday's race at 2pm. Stream every F1 race and more with a NOW Sports Month Membership - No contract, cancel anytime