Lewis Hamilton tightened his grip on a fifth world championship after a commanding win in Singapore on Sunday.

The Mercedes driver has moved 40 points clear of his rival Sebastian Vettel with just six rounds remaining.

Here, Press Association Sport looks at five things we learned from Sunday's race at the Marina Bay Street Circuit.

Unstoppable Hamilton in the form of his life

How do you solve a problem like Lewis Hamilton? That is the question for Sebastian Vettel and Ferrari after they were smashed out of the ball park by another emphatic performance from the British driver. A fortnight after he went behind enemy lines in Italy to pass both Ferrari cars and take a remarkable victory, Hamilton was at it again this weekend with a pole position lap from the very top drawer. From there, his win never looked in doubt. We didn't see the best of Hamilton for arguably the first 10 rounds of the season, but his performances en route to winning four of the last five races in Germany, Hungary, Monza and here at the Marina Bay Street Circuit have been among the most complete of his career. With Hamilton only getting stronger, it is surely now as case of when, rather than if, he will be crowned world champion.

Blame Vettel's blunders on Hamilton's brilliance

A school of thought has emerged in the paddock that Vettel's mistakes this year should be blamed on a poorly-run Ferrari team. The theory goes that Vettel would not have lost points in Azerbaijan (ran off the road attempting to pass Valtteri Bottas for the lead), France (collided with Bottas on the opening lap), Austria (handed a five-place grid penalty for blocking another driver in qualifying), Germany (crashed out from the lead) and Italy (spun after colliding with Hamilton) if he did not have to manage his team from the cockpit. Yes, there was evidence on show of Ferrari's curious management decisions when Vettel lost a place to Max Verstappen after he was called into the pits a) too early and b) then put on the wrong tyre. But every driver, even Hamilton, questions the calls made by their team. Perhaps, Vettel's mistakes are rather a result of going up against Hamilton, and not having the answers to beat him, than the failings at Ferrari?

Tyre-some rubber talk dominates Singapore race

The street track in Singapore is virtually impossible to pass on, so it was perhaps inevitable that strategy would be the talk of the town during Sunday's race. Tyres subsequently took centre stage. Unlike all of the leaders, Vettel took on the ultrasoft tyre during his one stop. We were told that the supposedly less durable tyre would stand no chance of making it to the end given that he stopped at the end of lap 14 of the 61-lap race. Yet, not only did Vettel make it to the chequered flag without pitting again, Bottas and Kimi Raikkonen (both on the more durable soft compound) made few – if any – gains on the German. While the varying tyre compounds do make a difference over one lap in qualifying, they proved once again that they have little bearing on the outcome of a race. Maybe tyre talk should be banned altogether?

Should blue flags be banned?

A rather uneventful race was spiced up by Romain Grosjean and Sergey Sirotkin squabbling for the minor positions and holding up Hamilton. Their on-track fight, and subsequent blocking of leader Hamilton, allowed Verstappen to close right onto the back of the Mercedes gearbox. Grosjean and Sirotkin were shown blue flags, an order that they must move out the way for a quicker car, but neither reciprocated. Indeed, Grosjean was handed a five-second penalty for ignoring the rule. Given the entertainment it provided, should blue flags be removed from the show altogether? It would certainly make for greater unpredictability and that cannot be a bad thing.

Weekend to forget for Force India

Esteban Ocon arrived here admitting he is set to be without a drive next year despite his obvious talent. Tough on the Frenchman? Yes. Unfair? No. Formula One, as with all top-level sport, is a ruthless business. Ocon was then involved in a rather unfortunate lap-one collision with his Force India team-mate Sergio Perez. It ended with Ocon in the wall at Turn 3 and his car written off. He appeared to suggest it was Perez's fault but Ocon's move was optimistic and the stewards took no action. Ocon's best bet for next year is now a reserve drive at Mercedes with the hope of getting a full-time seat again in 2020.