Max Verstappen faces a fight to take pole position at the Singapore Grand Prix after calling his Red Bull “unacceptable” in final practice.

As Carlos Sainz raced to the top of the time charts at the Marina Bay Circuit, Verstappen finished fourth.

The Dutchman is on an unprecedented 10-race winning streak with his Red Bull team unbeaten at the 14 rounds of the season so far.

But Verstappen bemoaned the handling of his car in the city-state, describing the upshifts in his Red Bull machinery as “unacceptable”.

He added: “These upshifts, what the f***. I am just struggling for rear grip. If I competed in drifting, I might win the race.”

Verstappen returned to the track in the closing moments of the one-hour running, ringing the neck of his Red Bull to move from sixth to fourth, 0.313 sec slower than Sainz.

But his struggles will give the chasing pack hope of finally stopping Verstappen and Red Bull with Ferrari holding the upper hand heading into qualifying later on Saturday.

Sainz and team-mate Charles Leclerc traded top spot in the two practice sessions here on Friday, with the former again fastest in the concluding running before the fight for pole.

Leclerc looked set to eclipse Sainz only to make a mistake in the second sector before backing out of his speediest lap, finishing fifth.

George Russell took an encouraging second for Mercedes, just 0.069 sec slower than Sainz, with Lando Norris third in his McLaren. Lewis Hamilton was sixth for Mercedes, within half-a-second of Sainz.

Verstappen’s team-mate Sergio Perez, who won here last year, finished eighth, 0.719 sec back.

Qualifying for the 15th round of 22 takes place at 2100 local time (1400 BST).