Lewis Hamilton admitted he “over-egged” his final lap in Saturday's qualifying for the Russian Grand Prix as he tried to find the pace to beat Mercedes team-mate Valtteri Bottas.

The championship leader said his mistake on the Sochi circuit cost him time, but he praised Bottas for doing a better job as the Finn grabbed only his second pole of the season.

“Big congratulations to Valtteri. He's been driving very well all weekend and did the better job,” said the defending four-time champion, who leads nearest rival Sebastian Vettel of Ferrari by 40 points in the title race.

Hamilton conceded that his last two laps “were not special at all”, but added: “You can't always get it right and at least we are still in the fight tomorrow.” He said he had been struggling in the middle of the lap.

“I knew I had to push a lot because I knew that (Bottas) would gain time so I needed about half a second and I just over-egged it a bit. I picked up some dirt on my outside tyres and there was less grip.”

The Briton said he expected the start to be “an interesting one” with Vettel attempting to make the most of a slip-streaming opportunity behind him from third on the grid.

“But after that, it's about strategy really, which we're all pretty much the same on... we'll just give it everything we've got.”

READ | Valtteri Bottas upstages Hamilton to take Russian GP pole

A bullish Vettel said he retained hopes of winning despite qualifying a distant third. The four-time world champion insisted that Bottas's half-second advantage in qualifying did not give a true reflection of Ferrari's race pace.

He also reminded the Finn of how last year's contest in Russia had unfolded when Vettel was on pole, but Bottas burst into the lead from third on the grid at the start.

“I just spoke to Valtteri and reminded him what happened last year, so maybe we can turn it around,” said Vettel. “It would be nice, but it depends on the start, the initial jump and then you know where you are.”

Vettel said it was “important to get as close as possible to them and then we'll see, but it's true they've been very quick -- so we'll see tomorrow. I think it should have been a bit closer, the gap, but we didn't have enough to be a threat.”

Vettel was half a second off Bottas's pace and four-tenths behind second-placed Hamilton.

“I am pretty happy with the car and it's not like there is a big issue with car balance. I think we reached our full potential today,” added Vettel.