They nevertheless finished second and fourth behind Sainz, separating Mercedes duo George Russell and Lewis Hamilton, who had dominated the day’s previous FP1 session at the Marina Bay track.
At the start of the only comparable practice session for qualifying and the race given its night start, Valtteri Bottas was the first driver out of the pits while the first riders were running on medium and hard tyres.
Bottas set the benchmark top spot at 1m45.839s on the mediums, before being pushed back by Mercedes duo Russell and then Hamilton, who finished their first flyer at 1m44.091s.
Russell stayed ahead in lap times until the end of the first 10 minutes, with the Briton’s first race including an off-track moment on the fast right-hand Turn 11 which leads to the Anderson Bridge at the lower end of the circuit.
He managed to get his Mercedes to stop, but only just before the barrier before reversing and continuing on his way.
Sainz then took over the lead with a 1m43.710s – also achieved on the medium tires of both Mercedes drivers – before Hamilton reclaimed the lead with a 1m43.668s a few minutes later.
At the end of the first third of the one-hour session, Sainz returned to the top of the lap times with a 1m43.237s which was the final average time for the next phase.
Charles Leclerc, Ferrari F1-75
Photo by: Simon Galloway / Motorsport Images
By this stage, it was clear the league leaders were having an unusual session, with Verstappen and team-mate Sergio Perez, and Leclerc yet to set a time.
Red Bull were working on both of their cars in their garage, while Ferrari reinstated Leclerc’s floor, which meant they were out of sync with the rest of the field when they came out.
Perez was the first of the trio to do so – heading immediately to perform a qualifying simulation on the softs, which Bottas had just used at this point before the halfway mark to skip the order to sit second behind the best of Sainz on the mids. .
Right off the start on his flyer, Perez had a massive slide out of turn 5 long straight which feeds into the first long straight of the track and he lost more time in the final two sectors to find himself nearly 1.5 s behind the lead time on the harder rubber.
Minutes later, Sainz completed Ferrari’s first soft run, bettering his first-place benchmark to 1m42.751s.
This happened despite the Spaniard cutting the wall out of Turn 19 to the 90-degree right which follows the brief underground section of the track that passes under the grandstand overlooking the short blast between Turns 17 and 18, which Perez and Esteban Ocon also made it onto their first qualifying mock laps.
Ocon’s time was good enough to take third place at this point despite the wallstrike, with Leclerc finally taking the track at this point.
George Russell, Mercedes W13
Photo by: Carl Bingham / Motorsport Images
He did it on the medium and finished a long race that featured a series of personal best laps – the first of which came in just 0.1 seconds slower than his teammate’s previous session lead time on the yellow-walled rubber.
As Leclerc continued to beat and improve his personal best, Sainz returned to the softs.
With just over 20 minutes to go, he improved the best time to 1m42.587s, with Leclerc, at this stage running in the wake of the other Ferrari, coming back in second 0.295s on his second-hand mediums.
That demoted Russell to third and Hamilton to fourth – the Silver Arrows pair having completed qualifying simulations on softs that featured fast opening sectors before losing time to Sainz as the round went on.
Perez had two more trials on softs during the late FP2 period which typically includes teams giving their drivers the task of conducting high-fuel race data collection exercises.
His second effort barely closed the gap to Sainz but, on his third try, he leveled the Spaniard in the opening sector before wasting so much time in sector two that he backed off and snagged. is directed to the pits.
During that action, Verstappen was out for a brief glimpse on the hardliners before returning to the Red Bull pit for another long stint of setup adjustments, which meant he languished in 15th heading into the final 15 minutes.
Max Verstappen, Red Bull Racing RB18
Photo by: Simon Galloway / Motorsport Images
It was clear that neither Dutchman, Perez or Leclerc would be able to perform the usual high fuel FP2 end races and indeed they were switched to qualifying mock races for the stages of closing – ending with round totals of eight, 12 and 13 respectively.
Leclerc went first on the softs and was nearly 0.2 seconds ahead of Sainz in the first sector before falling back level with his teammate’s best time after finishing the middle third and eventually posting a time that held him. second but at 0.208 seconds.
Shortly after, with just four minutes left in the session, Verstappen did even better in the first sector to lead Sainz by 0.2 seconds.
But he too came back to the same level at the end of sector two, then lost so much time in sector three – over 0.3 seconds – his personal best meant he only placed fourth behind the best effort on soft tires from Russell from the start of the session.
That pushed Hamilton and Ocon back to fifth and sixth in the final order, with Bottas and Fernando Alonso seventh and eighth, while Perez was ninth.
Lance Stroll completed the top 10 in a session which, as usual for the tricky street track, featured a series of lock-ups and dives on escape routes – but no one hit the walls hard enough to cause a stop.
The most dramatic moment in the proceedings was when Pierre Gasly – 14th fastest – had to quickly jump out of his AlphaTauri when he was pulled back into his garage as flames erupted from the car’s airbox.
The incident happened just over 15 minutes into the session, with the fire quickly extinguished just as Gasly emerged from his cockpit.