Lewis Hamilton’s pursuit of perfection has turned him into the complete racing driver, his Mercedes boss Toto Wolff has said.

Hamilton is edging ever closer to a fifth Formula One world championship, and he will head into the Russian Grand Prix on Sunday with a commanding 40-point lead over Ferrari driver Sebastian Vettel.

Hamilton, 33, has been in the form of his career of late, with superstar displays in Italy earlier this month, and then under the lights of Singapore a fortnight ago.

He has won four of the last five races, and led the way in practice at the Sochi Autodrom on Friday, finishing half-a-second clear of Vettel, who ended up only fifth.

“Lewis is certainly performing on a very high level,” Wolff, the Mercedes team principal, said.

“Without going into too much detail, he is in a good place in his life. He enjoys racing, and he enjoys the activities outside of racing. Give him a good car, and he is able to perform on a level that is unseen.

“What is also impressive is his constant development and his search for the optimum performance. He is the only driver I have ever heard say, ‘I haven’t driven well, so first we have to look at my driving and then we look at the data’.

“This constant drive for perfection is one of the reasons as to why he is such a complete racing driver.”

Hamilton won the opening two instalments of the Russian race staged here on the site of the 2014 Winter Olympics, but he was mysteriously off-colour last year.

He qualified fourth, and then finished a distant fourth. Ahead of Sunday’s race, one journalist put it to the Englishman that it was in fact the worst performance of his career.

It was a notion dismissed by the Mercedes driver. Then, in practice, his fine form continued as he finished top of the timesheets ahead of team-mate Valtteri Bottas to indicate that he, and his Mercedes team, boasting an upgraded package this weekend, are the ones to beat.

“Sochi has been one of the weaker circuits for me in the past, particularly last year,” Hamilton said.

“So I’ve done a lot of work to understand the balance and see where I can improve to try and rectify this, so today has been good in that sense.

“From every race we’re learning more and more and the last few races have helped us to really gauge which foot we need to start on for the weekend. It’s been a good day for us, so let’s hope that it continues on Saturday.”