Former Formula 1 driver Mark Webber has suggested Sebastian Vettel is still susceptible mentally as he considers how the 2018 title battle with Lewis Hamilton will play out.

Currently, the German holds an eight-point lead over the Mercedes driver as the season reaches its halfway point this weekend at Hockenheim, however, Vettel was in a similar position last year before his overaggressive tendencies led to the crash in Singapore, a moment that swung the battle in Hamilton's favour.

Webber also knows first-hand what it's like to work with with the four-time world champion as the pair famously fell out after a range of incidents as teammates at Red Bull from the memorable collision in Istanbul in 2010 to the 'Multi-21' saga at Sepang three years later.

Nowadays, bygones are bygones and the two get along, however, known for his outspokenness, that hasn't stopped the Australian from having a dig at his former teammate.

“[Vettel] does have flashes of a meltdown,” he told the official Formula 1 podcast.

“Sebastian has had those and does have those. I think he has a plan and often these meltdowns are outside our normal routine of a Grand Prix. So, Safety Cars.

“Abu Dhabi [in 2012] he’s been off behind the Safety Car, hitting DRS boards, we saw [the incident when Vettel banged wheels with Hamilton in] Azerbaijan [last year].

“So it’s amazing how he has this maximum intense focus and concentration that he can do. Winning off pole off the front, breaking the DRS, that was his signature punch. He was deadly with that.

“But as soon as there was another complication that became a little more tricky.”

This year too, despite insisting his approach would be more measured and less emotional, Vettel has had moments that have cost him, including two with Valtteri Bottas in Baku and France.

It isn't just uncertain race situations that seemingly rile the 31-year-old though, with Webber revealing the narrow operating window of the Pirelli tyres has often frustrated him.

“It’s still a little bit open. Are the tyres ready on the first lap, maybe we’ll do two timed or one timed? He often hated that," he said.

“He hated that. Hated that. Because it wasn’t bang, bang, German, what’s clear."

With the battle between Vettel and Hamilton taking so many twists and turns it's hard to predict what will happen next, however, with the consistency of the Briton making him so hard to beat, avoiding any silly lapses of judgement are going to be crucial between now and Abu Dhabi.