Max Verstappen topped the opening practice session for the Singapore Grand Prix on Friday, with team-mate Daniel Ricciardo second as Red Bull asserted their dominance at the top.
The pair were split by just 0.049s, whilst the gap to third-placed Sebastian Vettel was almost half a second. The Ferrari driver posting a best of 1m46.287s.
Mercedes' Lewis Hamilton – who trialled the Halo during an installation lap – was fourth ahead of team-mate Nico Rosberg, but both were over six-tenths off the Red Bulls, however their times were set on the hardest compound.
Rosberg also crashed at Turn 18 during one of his flying laps. The German went head on into the barriers, but was able to continue with a broken front-wing.
The second Ferrari of Kimi Raikkonen was sixth quickest.
The session began with a Virtual Safety Car after McLaren's Jenson Button ground to a halt at the pit entry, with the team confirming a fuel issue as the cause. He later rejoined the session and went P16, almost four seconds adrift of the leading pace.
Romain Grosjean was the third driver to hit trouble, failing to set a timed lap as he completed just two runs. He spent the session garage bound with Haas blaming a leak within the engine.
