The reigning world champion was forced to settle for fourth, his lowest finishing position since last season’s Korean Grand Prix.

After missing out on pole at the last race at Silverstone to team-mate Mark Webber, and being beaten in the race by Ferrari’s Fernando Alonso, all of a sudden chinks have appeared in his previously impregnable armour.

That was particularly evident over the weekend at the Nurburgring, with team principal Christian Horner revealing Vettel was far from comfortable throughout.

Another first for Vettel this season is that he has had his lead cut, although only by three points by Webber, with victor Lewis Hamilton and runner-up Fernando Alonso 82 and 86 points adrift.

But expressing unhappiness for the first time this season, and with the next race in Hungary on Sunday, Vettel said: “The weekend was a bit strange.

“I never felt 100% well in the car. There have been moments when I thought that everything would be back to normal, but in the end it wasn’t and issues surfaced.

“Now we have to sit down and analyse the reasons for all these hiccups because one thing became very clear this weekend – the others have caught up so we also have to keep up our development.

“The next race now comes around quick, with Hungary normally a good track for us, so we’ll see.

“But we have homework to do because McLaren and Ferrari were very quick in this race and we need to come back to the pace they have.”

Starting from third, Vettel lost that place to Alonso before making an uncharacteristic error in sliding wide onto a run-off area on lap 10.

Another followed later in the race when he was forced to use an escape road as he closed in on Ferrari’s Felipe Massa.

After staring at the rear of Massa’s car over the second half of the race, Vettel managed to leapfrog the Brazilian as the duo made their final pit stop just a lap from the finish.

It was the only bright spot of an otherwise unusually difficult weekend, with Vettel adding: “Basically we were not fast enough.

“When I lost the car at turn 10, from then on we knew P4 would be the maximum - and that’s what we then focused on.

“In the end I was able to take that thanks to my crew who did everything right.

“I tried to squeeze out everything possible up until the pit-lane speed limit, and when I reached my crew it was so close.

“Finally when I was released I saw the guys at Ferrari were still busy and that is when I knew P4 was mine. My guys won the pit-stop duel.”