Even though he made it look easy, Sebastian Vettel's cruise to a fifth victory of the 2013 season at Spa-Francorchamps was genuinely unexpected as far as the reigning world champion was concerned.

"I don't think we expected to be dominant here, and it surprised all of us actually - it's a great result," he said.

His boss, Red Bull team principal Christian Horner, agreed. "We didn't come here expecting to win today, so it's great to get a victory to start the second half of the season."

Vettel was at his imperious best when he passed Lewis Hamilton on the run to Les Combes on the first lap and then pulled away from the field, thereafter headed only briefly during the pitstops and eventually going on to win by over fifteen seconds from Ferrari's Fernando Alonso.

"He had an average start, but managed to position himself well going through the first corner, and he knew that the first run through Eau Rouge up the hill was going to be critical," commented Horner of how his driver had won the day.

As easy as the lap one pass looked, Vettel insisted that he really had no idea going into the race just how much - if any - performance the Red Bull had in hand over the competition.

"I think we knew going into the race that our race pace, compared to Mercedes, maybe gave us a little in hand, but we didn't know where we were compared to the others, especially Ferrari - and Lotus looked very quick in dry conditions also," he said.

Once Vettel was in the lead it seemed that the only thing that could throw a spanner in the works would be a late downpour and the team duly planned for that contingency just in case, but when the skies stayed clear it was plain sailing all the way to the chequered flag for Vettel.

"It wasn't clear if the rain was going to come at the end of the race," Vettel said. "So we kept pushing, but the gap we had by that stage meant we were able to control the race from there and the last couple of laps weren't too stressful."

It is a result that sees the 26-year-old's championship lead extended to 46 points over Fernando Alonso, a daunting margin for even the most stalwart of Vettel's competitors to contemplate. The dominant manner of his victory on Sunday will also have raised much trepidation in the hearts of his rivals.

By contrast with Vettel's perfect race, a poor start off the line meant for a frustrating final F1 Belgian Grand Prix for Mark Webber before he retires from the team at the end of 2013. The Australian explained that pre-existing clutch issues had been to blame for his poor getaway off the grid.

"The two practice starts before the race weren't great and so we were a bit worried about the clutch going to the start, which put us on to the back foot," he revealed. "We tried our best, but lost a couple of rows off the line which is not good.

"The bad start put us out of position and it snowballs from there, as you use up the tyres trying to getting to back into position," he continued. "We then had to try and clear people on the track, which was difficult, as we had set up the top gear to race in clean air rather than to pass.

"We did our best to tidy [Mark's clutch issue] up but he conceded a place to Rosberg off the start," commented Horner. "Once he was compromised in his positioning within the pack, he wasn't able to get a clean run through La Source and Alonso managed to get a run on him down the hill and pass him into Eau Rouge.

"Thereafter it was a matter of trying to find a way through, past the Mercedes and Ferrari ahead, but unfortunately whenever we got close enough we seemed to lose aero performance and so Mark couldn't get close enough to make a move," Horner added.

Despite that, Webber went on to finish in fifth place which brings another valuable ten points to the team in their pursuit of a fourth constructors championship in 2013.

By Philip Barclay