Singapore - Red Bull enjoyed a welcome return to the top of the timesheets after a few quiet races with Daniel Ricciardo and Max Verstappen setting the fastest times in the first practice session for the Singapore Grand Prix on Friday.
The demanding Marina Bay Street Circuit has traditionally favoured the Red Bulls and Ferraris, so it was no surprise to see the Italian team's Sebastian Vettel and Kimi Raikkonen clock the next quickest times.
Mercedes, meanwhile, opted for a different strategy, deciding not to use the fastest 'hypersoft' tyre compound throughout the session, making it difficult to evaluate championship leader Lewis Hamilton's sixth spot on the timesheets, especially after he locked his front wheels and momentarily veered off the circuit.
Ricciardo has failed to finish the past two Grands Prix since Formula One returned from its summer break but he again showed his street circuit prowess by clocking 1m39.711s in the baking Singapore sun.
Verstappen lapped in 1m39.912s to edge out Vettel by 0.085s but the German will be looking to improve over the weekend as he seeks to eat into Hamilton's 30-point championship lead with seven rounds remaining.
The session started in the mid-afternoon with the dusty, bumpy circuit difficult to navigate for drivers in conditions far removed from what they will experience on Sunday night when the lights go on.
Mercedes has already stated that it expects Ferrari and Red Bull to prove a handful over the weekend with team principal Toto Wolff explaining that it had used the first of three practice sessions to gauge the soft compound tyres.
"We were running a completely different programme to the other teams. We didn't run the hyper and concentrated on long runs for this session," Wolff said. "We need to attack and be flat out in the next sessions."
Renault also enjoyed an encouraging afternoon as Nico Hulkenburg finished fifth, ahead of Hamilton, with team-mate Carlos Sainz crossing the line seventh fastest, ahead of Valtteri Bottas in the other Mercedes.
Sauber's Charles Leclerc continued to show the sort of form that encouraged Ferrari to sign him as Raikkonen's replacement for 2019 by finishing ninth but his afternoon ended on a sour note when he crashed into a wall at Turn 13, mangling his front suspension. Leclerc apologised to his team on the radio as he left his car stranded in an escape road with two minutes left in the session, a sight that will disappoint his future employers, who will hope he does not make similar mistakes next season.
1 Daniel Ricciardo (Red Bull) - 1m39.711s
2 Max Verstappen (Red Bull) +0.201s
3 Sebastian Vettel (Ferrari) +0.286
4 Kimi Raikkonen (Ferrari) +0.775
5 Nico Hulkenberg (Renault) +1.394
6 Lewis Hamilton (Mercedes) +1.521
7 Carlos Sainz (Renault) +1.618
8 Valtteri Bottas (Mercedes) +1.718
9 Charles Leclerc (Sauber) +2.324
10Romain Grosjean (Haas) +2.397
11 Marcus Ericsson (Sauber) +2.697
12 Sergio Perez (Force India) +2.701
13 Kevin Magnussen (Haas) +2.741
14 Fernando Alonso McLaren +2.919
15 Esteban Ocon Force India +3.466
16 Pierre Gasly Toro Rosso +3.529
17 Brendon Hartley Toro Rosso +3.774
18 Lance Stroll Williams +4.138
19 Sergey Sirotkin Williams +4.325
20 Stoffel Vandoorne McLaren +5.449