Sebastian Vettel admits a battery issue on his Ferrari Formula 1 car acted as a “costly” blow in his hopes of taking pole position for the Belgian Grand Prix.

Vettel had to settle with second on the grid after ending up 0.7s down on chief title rival Lewis Hamilton as the duo battled it out for pole in Belgium. The German later revealed he was down on power on his final flying effort due after failing to recharge the hybrid system on his Ferrari.

"I think the way we set up normally it was fine to run until the end but I was surprised with myself when I crossed the line and saw that the battery was quite low, which was very costly,” Vettel explained.

"In the end we should've managed better as a team, but in these conditions it could've been a red flag in the last lap and then it doesn't matter, I always trying to open a gap in the last sector last corner, and slow down to charge the car - but obviously it wasn't enough at the end. We got caught out."

A downpour as Q3 was getting underway turned qualifying on its head and caused chaos as drivers returned to the pits in order to change onto intermediates tyres, having initially started the final segment of qualifying on slicks.

Vettel conceded Ferrari got caught out in the drama and “had a wobble”, leading to miscommunication in the pitlane while he attempted to return to the circuit after receiving a top-up of fuel.

"I think we had a wobble, I guess everybody had in these conditions," he said. "It was just not as calm as it could've been. Yeah, after that, well I mean looking back it's always very easy in these sessions [with the benefit of hindsight], but the lap that mattered was the last one - before that was nearly irrelevant other than keeping your tyres warm.

"But that you don't know, you don't know whether the rain increases again. In the laps I had before, I couldn't close also due to traffic, so I knew that if I close on them then the next lap will be compromised then the next lap could be drier, so what do you do? As I said it didn't feel like I got everything out for various reasons, therefore it was a very scrappy session.

"You saw also the others not putting enough fuel for the end, so it can be a lot worse."