Max Verstappen suggests his Red Bull RB19 is still not perfect in terms of set-up despite making gains in qualifying for the Bahrain Grand Prix.

The Dutchman recorded the 21st pole position of his career on Saturday to head team-mate Sergio Perez on the grid for tomorrow’s race.

Verstappen and Red Bull looked the runaway favourites during pre-season testing last week but struggled to translate that into pace this weekend.

Fernando Alonso was fastest in Free Practice 3 for Aston Martin, as he had been in Free Practice 2.

Verstappen was never far from the top of the timesheets but admits he struggled with the car throughout the weekend before making strides when it mattered.

“My whole weekend up until qualifying was very difficult,” he said.

“I couldn’t really find the comfortable balance I had in testing and I was just struggling a lot just to get the car together, really.

“I went into Q1 and everything already felt a bit better, but it was still not perfect but in a better direction.”

Verstappen mustered a 1:29.708s with his final flying lap in Qualifying 3, just over a tenth quicker than Perez was able to achieve.

Charles Leclerc was next best, almost three-tenths adrift of the pole time but the Monegasque did manage to save a set of tyres for the race.

“I went left and right and back to the middle to find a bit of a compromise,” Verstappen said of chasing car set-up during practice.

“That’s a bit unusual that you make such big changes.

“Luckily in qualifying that’s probably the best balance I’ve had throughout the weekend so far.”

With qualifying now behind him, Verstappen is confident the Red Bull will come into its own in race trim.

“That should normally be our stronger point that the one lap is,” he said of his long-run pace.

“Hopefully we can show that again tomorrow.”

The Bahrain Grand Prix begins at 18:00 local time on Sunday (02:00 AEDT Monday).