Lando Norris has admitted he is unsure whether McLaren will be able to fix an issue with his car that is causing a loss of straight-line speed ahead of this weekend’s Singapore Grand Prix.

The reigning world champion was in fine form as he claimed three pole positions and two victories in four races spread either side of the summer break, but he has since been off the pace in Azerbaijan and Malaysia.

Norris only qualified fifth at both events, was taken out of the Azerbaijan Grand Prix in a crash and could only manage ninth in an error-strewn display as Malaysia hosted the Bahrain Grand Prix.

The issue, which made Norris slower than his team-mate Oscar Piastri in certain parts of the Sepang International Circuit, appears to be being caused by his power unit, but McLaren have yet to find the exact issue.

Asked whether the team can fix it for the upcoming Sprint weekend in Singapore, Norris told Sky Sports F1: “I have no idea.

“The team are trying but I’m losing almost two tenths a lap. Two tenths a lap over 55 laps is just painful as hell. It’s making my life pretty damn difficult.

“There are also other things. In Malaysia I could have done better. I can’t just have that. That’s not just an excuse.

“There are things I can do better and the team as well.”

Stella: Rivals may have developed car with bigger steps

McLaren boss Andrea Stella admitted that some of the team’s rivals may have “developed their car with bigger steps” after successive underwhelming showings.

The reigning constructors’ champions appeared to be back in the mix for victories when their upgrade package at the Hungarian Grand Prix before the summer break helped Norris deliver the team’s first grand prix pole and victory of the season.

However, despite McLaren having added more upgrades to their car, Mercedes’ George Russell claimed a dominant win in Azerbaijan before Max Verstappen exhibited Red Bull’s progress by triumphing in Malaysia.

Stella said: “We see a scenario in Formula 1 which seems to be changing pretty rapidly.

“In Hungary, we took some upgrades, and we were in condition to have a pole position in Hungary and Zandvoort and then we were in condition to do pole position and pretty much victory in Madrid without the Virtual Safety Car.

“Then very rapidly and interestingly, as we took upgrades as well, the picture changes.

“I think we have to take a look at our own development. We don’t see any anomaly in our data, but we have to acknowledge that potentially some competitors have developed their car with bigger steps than we did.”

The extremely high temperatures and rough track surface in Malaysia created a potential outlier in terms of conditions, which has left Stella with some hope that McLaren could return to form in Singapore.

“There are very specific conditions in Malaysia, so I think we should give ourselves more time,” he added.

“I’m sure this is the same kind of review that we’ll have next door at Mercedes. It’s a very special condition in Malaysia, so I think we have to understand better the behaviour of the cars.

“I think we need to give ourselves some more time. I’m personally not in condition to say if Singapore will be now more suitable or not, because from a track layout point of view, we thought that Sepang would be a decent circuit for us.

“This is because of the uncertainty caused by the new scenario from a competitiveness point of view, but also because we might have to understand a bit better the upgrades that we took ourselves, and Singapore will give us a better answer.”

Formula 1 heads straight to Singapore for the last Sprint weekend of the season with track action starting this Friday, live on Sky Sports F1. Stream Sky Sports with NOW – no contract, cancel anytime