Lewis Hamilton strengthened his grip on top spot in the Formula One drivers' championship with victory in Singapore as Sebastian Vettel's strategy let him down.

The Mercedes driver benefited from a questionable Ferrari tyre choice and a Max Verstappen overcut on the German to extend his championship lead to 40 points with six races to go, as Vettel finished third.

It was largely plain sailing for Hamilton after a spell behind the safety car in the opening laps, following a collision between Racing Point Force India team-mates Sergio Perez and Esteban Ocon, which planted the latter's car into a wall.

Hamilton certainly came under no pressure from his main challenger in the drivers' standings and it was only during a brief period of traffic that Verstappen could get close.

The Briton emerged from that tailback with his lead intact - if a little narrower than before - and was soon putting space between himself and Verstappen once again when he hit clean air.

The front three looked locked in as they spread out 10 laps from the end, with Vettel eventually crossing the line more than half a minute behind second-placed Verstappen.

Mercedes' Valtteri Bottas finished fourth, ahead of Kimi Raikkonen and Daniel Ricciardo, with Fernando Alonso, Carlos Sainz Jr, Charles Leclerc and Nico Hulkenberg completing the top 10.

ULTRA-FRUSTRATED VETTEL

Vettel's title hopes are slipping away after another disappointing outing, which can be attributed in part to the strategic disaster of his first pit stop.

Under pressure to make their move after Hamilton stepped up the pace out in front, Ferrari brought Vettel in after 15 laps, switching him from the rapidly deteriorating hypersofts to ultrasoft tyres.

Hamilton pitted a lap later but instead opted for the soft tyre – as did the rest of the leading drivers with the exception of Ricciardo.

The stops left Hamilton and Vettel sitting either side of Perez and the German's time spent behind the Force India proved costly, allowing Verstappen to pit and emerge in front of the Ferrari.

Vettel was faced with an incredibly long stint to negotiate on the ultras and, while he managed to make it to the finish, he was unable to mount any sort of challenge for second, let alone trouble Hamilton out in front.

UNFORTUNATE OCON

You have to feel for Ocon. The promising French driver looks to be on his way out of Force India following the Racing Point takeover and is running out of options for 2019.

With that in mind, he really needs to impress over the remaining races of this season but was robbed of the opportunity after a first-lap collision with Perez, whose seat appears more secure.

Ocon was driving on the outside of Perez at Turn 3 in a blindspot for his team-mate, who shunted him into the wall, later confirming over team radio that he had not seen his colleague – although the Mexican's claim that he had no room to accommodate Ocon appeared wide of the mark.

Some may question the wisdom of attempting an overtake around the outside of Turn 3. Ocon could well be among them as he reflects on a missed opportunity to showcase his talents.

Perez's race got no better, as he was deemed culpable in a collision with Sergey Sirotkin and served a drive through penalty later in the grand prix.

RACE TO THE FINNISH

As Hamilton, Verstappen and Vettel sat comfortably in their positions, it was their team-mates who provided the entertainment in the closing laps.

First, Raikkonen - on fresher tyres - closed the gap on fellow Finn Bottas in the race for fourth, before Ricciardo, who switched to the ultras much later than Vettel, made it a three-way battle.

Ricciardo's challenge faded with his tyres and Bottas' determined driving through frustrating traffic saw him hold on for a hard-earned fourth-place finish.