Red Bull displayed their race-winning potential at the Singapore GP as Daniel Ricciardo topped a competitive first practice session.
The Australian's 1:42.489 was the absolute lap record around the Marina Bay circuit, with Ferrari's Sebastian Vettel and Ricciardo's Red Bull team-mate Max Verstappen a tenth of a second adrift.
Lewis Hamilton finished fourth and was 0.4s off the pace, but both he and Mercedes team-mate Valtteri Bottas posted their best ultrasoft-shod times earlier in the session when conditions were even less representative after rain showers earlier in the day.
But it was Red Bull, confident of challenging Ferrari and Mercedes to seal a second race win of the season, who have laid down their marker - further strengthening expectations that Formula 1's marquee night race could feature a three-way fight for victory.
"I think, like Hungary, we see Red Bull don't hide as much as Ferrari," said Sky F1's Paul di Resta. "Ultimately I think as the weekend develops I would expect Vettel to be taking control.
"I think the closest battle between team-mates we will see will be between Verstappen and Ricciardo."
Sergio Perez, who has scored points in all of his Singapore GP appearances, was an impressive fifth for Force India.
This weekend's grand prix has also played host to a series of interlinked engine and driver moves. McLaren have ditched Honda, while a Toro Rosso-Honda partnership and a Carlos Sainz move to Renault have also been confirmed.
When's the Singapore GP on Sky?
And, not for the first time this season, Fernando Alonso made his frustrations heard about McLaren's Honda engine, despite finishing the session in eighth.
After earlier claiming he had "no power" the Spaniard yelled, "no, please no!", when asked if he would like another flying lap before insisting that McLaren could be topping the timesheets.
The engine/driver announcements at the Singapore GP
McLaren are exiting their Honda works partnership
McLaren are joining Renault's customer roster
Toro Rosso are switching from Renault to Honda power
Carlos Sainz is replacing Jolyon Palmer at Renault in 2018