Vettel has not finished on the podium in the last four grands prix as Red Bull has overtaken Ferrari in the constructors' championship, the Milton Keynes team now 14 points ahead.

The German driver is 97 points behind Lewis Hamilton in the standings with nine races remaining.

Vettel admitted the last few races have been very difficult for Ferrari, but he is optimistic that they at least have helped the team understand what needs focusing on to improve.

"The last couple of races have been tough for us, but very, very useful, as we understood a lot about our car and we know what to focus on," said Vettel.

"It wasn't entirely clear after the first couple of races but it became more and more evident.

"Obviously it's a harsh way to find out, not being as competitive as we want to, but I think we know what to do.

"It's not easy to change overnight but there is a plan and the second half should be stronger in that regard."

He added: "The last couple of races have been tougher for us and better for them [Red Bull], but I'm sure the second half will be better for us again and we'll be more competitive."

Vettel finished his home grand prix in fifth position, over 30 seconds behind race winner Hamilton.

The German conceded Ferrari simply did not have the pace to do better.

"Certainly not happy. Obviously racing at home is something special and in that regard it wasn't a special race.

"I think struggled to get the balance right and the car was sliding a little bit too much, which cost us a bit of life on the tyres. To sum it up, we were not quick enough.

"Unfortunately we were a bit too far form the cars in front, especially after the first two stints."