Sergio Perez expressed his concerns about Red Bull's potential at the Singapore Grand Prix this weekend after citing a lack of balance during Friday's practice sessions.

Lando Norris set the pace, finishing 0.058 seconds clear of Ferrari’s Charles Leclerc, with the Perez's team-mate Max Verstappen 1.294secs off the pace in 15th. 

Perez managed a eighth place finish, just behind the Mercedes of George Russell and the RB of Daniel Ricciardo. 

The Mexican will be hopeful of a better outcome in this weekend's race after crashing out on the penultimate lap in Baku last week after an incident with Carlos Sainz. 

There is no driver in this season who has not finished a Grand Prix on more occasions than Perez (three level with Alex Albon and Yuki Tsunoda).

He has now gone 11 races without finishing in four seasons for Red Bull, his highest number of retirements with a team, surpassing the 10 in five years for Force India.

Reviewing the two practice sessions, and whether any progress was made between FP1 and FP2, Perez said: “I think we improved a little bit, but still we are lacking quite a lot of balance.

"It’s quite difficult out there to put a lap together, [so] it’s not looking great at the moment."

Perez went on to comment that the level of Red Bull’s struggles “took us by surprise” despite the problems they faced at the Marina Bay street circuit last season.

“Definitely we’ve got some work to do overnight because we are quite far [behind],” said the Mexican, who was 0.871s down on pace-setting McLaren rival Norris.

“We are nearly a second off the pace, so we need quite a big change to be able to come through. We’ll see what we’re able to do.”