Jackie Stewart says Lewis Hamilton must improve mind-management in order to deliver full potential

Amid a fresh focus on Hamilton's driving, following two separate incidents with Felipe Massa over the Singapore Grand Prix weekend, Stewart has said he does not understand why the British driver is not delivering his full potential at the moment.

"I am a bit confused because he certainly knows how to drive and has a very large amount of natural talent," Stewart told AUTOSPORT. "But if he is going to be a great driver he cannot have serial incidents. And none of the great drivers ever drove in that fashion.

"He has all the skills but somehow or other, he jumps out of gear mentally - like in Singapore] qualifying, leaving the pits. I cannot believe he nearly had an incident that would have taken him out of qualifying.

"The race incident was again uncalled for, so I think he needs to think about his mind-management. He has the skills, and he has the abilities, but unfortunately he is having too many incidents.

"Michael [Schumacher] has had the same problem, but all the great drivers, the Fangios, Jim Clarks, Niki Lauda, myself - we didn't have many accidents."

Hamilton was on the receiving end of a hefty criticism from Massa after the Singapore GP, and the pair had an angry exchange in front of the television cameras - which prompted the McLaren driver to cut short speaking to the press.

His father Anthony Hamilton believes that management issues may be the key factor in the current troubles, as he thinks XIX Management should be giving him more support.

"His management need to do more," Hamilton's father told the BBC. "What I will say is look up the paddock; every driver that's got a driver manager, the manager is here [in Singapore] and in the driver's life."