Cape Town - Former Red Bull driver Mark Webber has labelled Max Verstappen as "flaky" in practice and qualifying sessions, putting pressure on himself and his mechanics.
Verstappen has struggled to make an impression this season due to a whole host of reliability problems, but Webber feels the Dutchman is not completely blameless for his disappointing campaign so far.
"Both of the [Red Bull Racing] guys have driven well this year, but Max has probably been a bit flaky in terms of the build-up to the races through the weekend," said Webber via Motosport.com.
"He's been going off the road a lot on Friday and Saturday, which puts pressure on mechanics getting the car ready. I'd like to see him on the road a bit more, but he's pushing the limits.
"When it comes to Sundays, he hasn't made many mistakes at all, it's been a lot of high-profile reliability retirements where he's lost a truckload of points, so that's been hard for him to swallow."
Webber went on to praise his fellow countryman Daniel Riccardo, believing that he is the most consistent driver in Formula 1.
"Daniel is just so solid on Sunday afternoons, he's the most reliable driver in F1 in that you know what he's going to deliver week-in, week-out," he added.
"He's always got the most out of what they've given him and it's hard to see how he could have done much more.
"We all expected such great things from this car this year, but it came out the box very poorly. They had a lot of catching up to do.
"With Renault [engines], it's unfortunately a little bit of a broken record, 'we haven't got this, we haven't got that' – it's been going on for five years. [Red Bull] have to make a car a second faster than everyone else, maybe."