Lewis Hamilton has extended his lead over Nico Rosberg in the Formula One world championship after romping to victory at the Belgian Grand Prix.

Hamilton, starting from pole for the sixth consecutive race, made no mistake as he eased to the chequered flag in convincing fashion.

Rosberg, slow off the start-line, recovered to finish second with Romain Grosjean benefiting from Sebastian Vettel's late puncture to take the final spot on the podium.

On Formula One's return to action after a four-week summer break, much had been made of the new start procedures introduced for Sunday's race.

The responsibility was being placed back in the hands of drivers - as opposed to the directive of their pit wall - and the premise was that it would lead to unpredictable starts and more dynamic racing.

And it was a tale of contrasting fortunes for the men who occupied the front row.

Hamilton, sluggish off the line at the last three races, enjoyed one of his best getaways of the season. Rosberg, in contrast, slumped to fifth.

Sergio Perez, who started from fourth, was quickest out of the blocks in his Force India. He drew alongside the Mercedes driver on the run down to Les Combes - the scene of Hamilton's collision with Rosberg last year - but Hamilton held the inside line and held off the challenge from the Mexican.

Daniel Ricciardo, winner here last season, was up to third in his Red Bull. The Williams of Valtteri Bottas was ahead of Rosberg, but it did not last for long. Rosberg, set to become a father for the first time next week, made his move on the Finnish driver at the chicane towards the end of lap one to take fourth.

Hamilton then laid down the gauntlet to his rivals at the sharp end of the pack with a number of impressive laps. By the end of lap four he had moved clear of Perez and was already five ahead of Rosberg. From there the race, which saw none of the rain which had been forecast, was all but over.

Ricciardo was the first of the leading pack to pit at the end of lap six. Perez promptly followed which promoted Rosberg up to second, almost nine seconds behind his championship rival.

Rosberg made his first stop at the end of lap 11 and his superior pace saw him rejoin the track ahead of Perez for a net second place. Perez, in his Mercedes-powered Force India, drew alongside Rosberg on the Kemmel Straight, but just as his team-mate did on the opening lap the German held position.

Hamilton stopped for a change to the prime tyre on the following lap. He retained the lead, but lost the best part of five seconds to his team-mate. Rosberg now trailed the leader by a little over three seconds.
Ricciardo's race then came to an abrupt end as he stopped with a mechanical issue on the pit straight.

The virtual safety car was deployed to slow the field down, but when it was withdrawn a little over two laps later, Rosberg had slashed the gap to Hamilton from a little over three seconds to nearer two.

"Nico is definitely closer than when the VSC came out," Hamilton observed over the team radio.

He had a point, but it did not matter. Rosberg was unable to get any closer, and for Hamilton, it was yet another regulation win, the 39th of his career, his lead in the championship extended to 28 points.

Elsewhere, Williams were left embarrassed when they fitted three option tyres and one prime tyre on Bottas' car. The different tyre compounds are defined by yellow, for option, and white for the prime. He was hit with a drive-through penalty and his race scuppered.

Retaining the comical theme, Jenson Button suggested that McLaren had "forgotten to connect the batteries". Down on power, he limped home in 14th ahead of only the Manor duo of Roberto Merhi and Will Stevens. Fernando Alonso was just one place better off on another sour day for McLaren.

Grosjean, who qualified fourth but was demoted to ninth after a gearbox change, then took the final spot on the podium after Vettel's puncture.

The four-time world champion, in his 150th race and who won last time out in Hungary, finished outside of the points.

Behind Grosjean, Daniil Kvyat was fourth for Red Bull, Perez fifth and Felipe Massa sixth for Williams. Kimi Raikkonen crossed the line in seventh for Ferrari with Max Verstappen, the unfortunate Bottas, and Sauber driver Marcus Ericsson rounding out the top 10.

Hamilton said: "We have had such a great crowd here this weekend, it has been incredible. For me it was just an amazing weekend and an incredible job done by the team. Today was a dream, the whole weekend, the car was fantastic."

With the crowd beneath him chanting "Lewis, Lewis", Hamilton added: "Nico had good pace but I was able to answer most of the time, so I was fairly relaxed at the front and the car was feeling great."

Rosberg said Hamilton deserved his sixth win of the season.

"I completely messed up the start so it was very annoying," he said.

"I fought my way through and gave it absolutely everything - we were both on the edge the whole way through - but Lewis did a great job and deserved to win."