A typical summer afternoon welcomed the opening practice session for this year’s Singapore Grand Prix, track temperature recorded around 45°C. Very early on track, along with the likes of Stroll and Sirotkin, was Sebastian Vettel, who was sporting traces of flow-viz around the floor and the rear end, areas where Ferrari focused their development after Monza, and kicked off his session with a 1m, 47.8 seconds long laptime, soon followed by Räikkönen’s 44.6, Bottas’ and Verstappen’s 44.7. Bottas’ subsequent effort was the first to dig under the 44s barrier, stopping the clock at 1:43.428, 4 tenths clear of Verstappen and 3 tenths of Vettel, Mercedes’ times – including Bottas’ next in 42.4 and Hamilton’s 42.9 - having been set on Ultrasoft tyres as opposed to Ferrari’s Hypersoft and Red Bull’s Soft.
Half an hour past the beginning, the silver pair climbed up to 42.0 (Hamilton) and 42.1 (Bottas), followed by Ricciardo in 42.4 and Verstappen in 42.8, both on the yellow compound. Hülkenberg led the midfield in 5th place with a 1:43.0 achieved on Soft tyres, soon displaced by a 42.4 courtesy of Sergio Perez on the pink compound. Ricciardo was the first to break the 42s barrier as he stole the lead with a 41.8, still on Soft tyres. Vettel plummeted down to 7th with Räikkönen in 13th as Ferrari worked on important setup changes inside their garage, Mercedes still on track working on Soft-tyre pace and regaining the top of the leaderboard thanks to Bottas’ 1:41.4 and Hamilton’s 41.2.
Rejoining the session with 35 minutes to go, the Ferrari pair smashed that record with a 39.9 (Vettel) and a 40.3 (Räikkönen) on Hypersoft tyres, the same that brought an updated Renault up to 4th (Sainz 41.3) and 6th (Hülkenberg 41.6, later enhanced to 41.1).
Red Bull then showed their potential as Verstappen went 2 tenths far from Vettel’s benchmark, but it was the Aussie who raised the bar by a further two tenths; the Dutchman improved to 39.9 later on to make it a 1-2.
Mercedes began race-pace work 15 minutes to the end and lapped around the 1:46s on Soft tyres which showed early signs of blistering. Red Bull’s pace in turn was around net 45s, Ferrari's around 44.6 as their future racer Charles Leclerc bent his front right suspension against the wall at the closing of the session, still managing to complete FP1 with a promising 9th place.