The 28-year-old lapped the 5km Marina Bay observe in a single minute, 42.587 seconds to finish the day 0.208 seconds faster than Leclerc.
George Russell continued to point out promise for Mercedes, after workforce mate Lewis Hamilton went quickest in Friday’s opening session, with the third-fastest time, 0.324 seconds adrift.
That put the Briton lower than a tenth of a second away from birthday boy Max Verstappen, who was second throughout the first hour of observe however spent a lot of the floodlit second session within the storage, solely popping out within the closing minutes to set the fourth quickest time.
The Purple Bull racer, who turned 25 on Friday, is 116 factors away from Leclerc and 125 forward of workforce mate Sergio Perez within the general standings.
Sunday’s race will provide him his first likelihood of clinching a second successive title with the Dutchman needing to attain not less than 22 factors greater than Leclerc and 13 factors greater than Perez to get the job achieved.
Hamilton, whose effort in Friday’s opening session put him on the high of the timesheets for the primary time this season, ended the day fifth.
Esteban Ocon was sixth for Alpine forward of Alfa Romeo’s Valtteri Bottas and the opposite Alpine of Spaniard Fernando Alonso.
Perez was solely ninth within the different Purple Bull, additionally logging low mileage, with Canadian Lance Stroll rounding out the top-10 for Aston Martin.
Thai racer Alexander Albon, who underwent appendicitis surgical procedure and suffered respiratory failure from post-operative anaesthetic issues earlier this month, was once more sixteenth quickest for Williams.
He accomplished a complete of 45 gruelling laps of the punishing Marina Bay observe over each classes.
Pierre Gasly endured a fiery finish to his session along with his AlphaTauri spewing flames from its airbox because it was wheeled again into the storage.
The Singapore Grand Prix, which takes place at evening in opposition to a backdrop of glittering skyscrapers and has established itself as one of many sport’s hottest races, is returning to the calendar for the primary time since 2019 this season.
The race was absent over the last two years because of the COVID-19 pandemic.