Monaco - Daniel Ricciardo lapped Monaco's metal-fenced streets in record time on Thursday as Red Bull dominated practice for Formula One's most glamorous grand prix.
The 28-year-old Australian set track record times in both sessions, first with a one minute 12.126 lap before lunch and then obliterating that mark in the afternoon with a scorching 1:11.841.
That compared to Kimi Raikkonen's 2017 pole position of 1:12.178 for Ferrari, the previous fastest around the Mediterranean principality's unforgiving streets and harbourside.
Dutch team-mate Max Verstappen was second quickest in both sessions as Red Bull lived up to expectations that it would be the team to beat on a tight and twisty circuit where aerodynamics matter more than engine power.
Verstappen, 20, was summoned to see the stewards after reversing onto the track in the opening session when he ran off at the first Sainte Devote corner, but they decided to take no further action.
Championship leader Lewis Hamilton and closest title rival Sebastian Vettel were third and fourth respectively in the morning before reversing those positions in the afternoon.
Vettel's best time of 1:12.413 after lunch compared to Hamilton's 1:12.480 in the earlier practice, but he was still more than half a second slower than Ricciardo.
Hamilton leads Vettel, last year's winner in Monaco, by 17 points after five races.
Drivers had predicted before the session started that lap records would tumble thanks to the new hypersoft tyres which are making their competitive debut this weekend and track resurfacing.
Ricciardo was third in Monaco last year, after taking pole and finishing second in 2016, and is aiming to take the final step on Sunday.
"Both drivers have got a good feel for the car, the car's working quite nicely, but it's only Thursday morning," Red Bull principal Christian Horner told Sky Sports television.
"We have had a competitive chassis all year and of course the straights are a bit shorter here, so that concertinas it all together."
Raikkonen was fifth fastest in both sessions while Valtteri Bottas was seventh and then sixth for Mercedes. Mexican Sergio Perez, who holds the race lap record of 1:14.820, was eighth for Force India in the morning.
McLaren's Fernando Alonso, who missed last year's race to compete in the Indianapolis 500 instead, had a difficult opening session with his car suffering problems with its brake-by-wire system.
The double world champion had a better afternoon and finished ninth fastest.
Russian rookie Sergey Sirotkin hit the wall in his Williams in the morning, limping back with a puncture, but went out again and was 10th fastest. He then dropped back to 15th in second practice.
Father and son world champions Nico and Keke Rosberg, both retired, entertained the crowd between the sessions by lapping the circuit in their title-winning cars.