It took Vettel just a few corners to sweep past pole man Hamilton into the lead
Caterham's Giedo van der Garde was another qualifying star, making it to 14th on the grid
In qualifying Lewis Hamilton seized his fourth pole position in as many races
Having looked set for pole at one point, Paul di Resta qualified a strong fifth
Both Marussia drivers, Max Chilton and Jules Bianchi, got through to Q2 during qualifying
Rosberg ended the race in fourth place, with the chasing Button sixth
Front-row men Vettel and Hamilton chat ahead of the Belgian GP
Reigning world champion Sebastian Vettel increased his stranglehold on this year's points standings with a dominant victory in the Belgian Grand Prix at Spa-Francorchamps. The Red Bull Racing driver was easily the class of the field as he cruised to his fifth win of the season.
On Saturday, Lewis Hamilton seized pole position in a thrilling qualifying session held in mixed track conditions. It was the Brit's fourth consecutive pole start, although he conceded that the Red Bulls of Vettel and team-mate Mark Webber were still likely to be faster than his Mercedes during the race.
So it proved, for although Hamilton led off the line, Vettel breezed past as they exited Raidillon and sped down the Kemmel Straight.
That was the last Vettel's rivals would see of his Red Bull apart from during the pitstop shuffles.
Ferrari's Fernando Alonso had qualified a lowly ninth, but come the race he was in typically feisty mood, overtaking a slow-starting Webber, who had clutch issues, as they sped down to Eau Rouge on the opening lap. The Spaniard then made good use of the DRS to sweep past Button on the Kemmel Straight on lap five to claim fifth place, and dispatched Rosberg in the same manner two laps later.
When Hamilton came in to change tyres for the first time on lap 12, he rejoined right behind Romain Grosjean and got embroiled in a fight with the Frenchman. It delayed Hamilton just enough for Alonso to rejoin right on the Mercedes racer's tail when he made his tyre stop. Both drivers cleared Grosjean before Hamilton ran slightly wide at La Source hairpin, allowing Alonso to nip ahead on the run down the hill to Eau Rouge.
The second Mercedes of Nico Rosberg finished fourth. The German came under pressure from Webber in the closing stages, but was able to keep clear enough of the Australian to ensure he couldn't deploy the Drag Reduction System to attack on the straights.
Jenson Button qualified and finished sixth in one of his most competition races of the season. He ran long into the race before making his first pit stop to open up the possibility of using a one-stop strategy. Indeed, he briefly led the grand prix after Vettel had come in for fresh rubber on lap 14.
But Button felt he should have remained out on the first set of tyres for a couple of extra laps. It left him in a strategical no-man's land, and when his front tyres began to wear heavily McLaren decided to deploy a two-stop strategy. It ruled out any prospect of a surprise podium finish for the 2009 world champion, but kept him in a solid points-scoring position after a more encouraging race.
Felipe Massa was hampered by a handling imbalance in the opening stages of the race, but recovered to overtake one-stopping Grosjean for seventh position in the closing laps.
Paul di Resta underlined his talent by qualifying a brilliant fifth in his Force India, but in the race he bogged down off the start line and fell back to seventh position. It was the start of a frustrating afternoon that ended with him getting punted into a spin by the out-of-shape Williams of Pastor Maldonado.
Kimi Räikkönen was another retirement. Having spent most of the race with brake dust belching from his front left wheel, his race came to an end when his over-worn brakes finally failed as he battled with Felipe Massa.
Vettel's win has put him 46 points clear of Alonso in the points standings, with Hamilton a further 12 points behind.
Belgian Grand Prix, 25 August 2013
1 Sebastian Vettel (Red Bull)
2 Fernando Alonso (Ferrari)
3 Lewis Hamilton (Mercedes)
4 Nico Rosberg (Mercedes)
5 Mark Webber (Red Bull)
6 Jenson Button (McLaren)
7 Felipe Massa (Ferrari)
8 Romain Grosjean (Lotus)
9 Adrian Sutil (Force India)
10 Daniel Ricciardo (Toro Rosso)