Sebastian Vettel has warned the rest of the Formula 1 grid that Mercedes have returned to their "usual level of competitiveness".

The Ferrari driver, who dominated from start to finish in winning the Singapore Grand Prix last weekend, was unable to match the Silver Arrows as the Constructors' champions locked out the front row of the grid at Suzuka.

However, Vettel is concerned that Mercedes have regrouped and could run away with Sunday's race.

He told reporters: "It was a tricky session for myself. I didn't really get going at the beginning, I couldn't feel the car so I struggled a bit to find the right balance. On my second run on the medium tyres in Q3, there was a big improvement as compared to the lap I had done in Q2, as if the car had 'become alive'.

"In the end we can be reasonably happy, I had a decent lap and I was a lot happier than previously; having scored a lap time which is competitive. Third place on the grid would have been the maximum today, but I missed this by one position.

"Mercedes are back to their usual level of competitiveness, as we have seen – unfortunately – all year. They will be the ones to beat tomorrow, but for sure we will try everything we can, even if we may expect stronger competition from Red Bull Racing and Williams."

Vettel will start from fourth after Valtteri Bottas beat the German to third on the grid.