In the sweltering heat of the Singapore Grand Prix, Lewis Hamilton turned up the heat on Sebastian Vettel a notch further.

Hamilton won comfortably from pole position on Sunday, extending his Formula One championship lead over Vettel to 40 points.

Winning from pole on one of the hardest tracks for overtaking in F1 was nothing special in itself. But Hamilton's masterclass in qualifying was exceptional as he recorded one of the best pole positions of his career — described as epic within his Mercedes team.

It afforded him a more relaxing race than expected — heat aside — given Ferrari's advantage during practice this weekend.

Considering Vettel makes more mistakes than Hamilton, a 40-point gap looks a huge advantage with only six races left.

Especially as Hamilton has no intention of easing up.

The British driver is on a major roll after winning four of the past five races, pinning Vettel firmly on the ropes in their bid for a fifth F1 title.

"I think the approach I have is working really well, so I don't see the point in changing," Hamilton said after his seventh win of the season and 69th in F1.

"I've been (around) a long, long time and I know I can't get ahead of myself, we can't get ahead of ourselves," Hamilton said. "I truly think we can deliver like this for the rest of the season, and that is the goal."Red Bull driver Max Verstappen was nine seconds back in second place, with Vettel way back in third.

"We didn't come here expecting to lose 10 points," said a dejected Vettel, who trailed by 30 heading into Singapore.

Vettel's championship bid crumbled when he crashed from pole here last year and went on to lose the title by 46 points to Hamilton.

It is looking increasingly like a repeat scenario for the Ferrari driver, who is in disappearing into Hamilton's slipstream.

Vettel was unhappy with his team after qualifying in third place behind Verstappen, and the German driver sounded irritated during Sunday's race after a team strategy error to send him into the pits for a tire change before Hamilton failed to work.

Instead he lost position and crucial points, dropping back behind Verstappen having earlier overtaken him.

"We tried to be aggressive in the beginning and obviously it didn't work out," Vettel said. "I think today, with the way we raced, we didn't have a chance. I said before the weekend we can only beat ourselves and today we didn't get everything out of the package."The only thing bothering Hamilton seemed to be the conditions. Despite the night-time start, the temperature was around 30 degrees Celsius (86 Fahrenheit) and the humidity intense.

"I'm spent," Hamilton said moments after victory, crouching down by his car.

His teammate Valtteri Bottas was fourth ahead of Ferrari's Kimi Raikkonen and Red Bull's Daniel Ricciardo. Two-time F1 champion Fernando Alonso, who won the inaugural race here 10 years ago, was seventh for McLaren.

Hamilton's stunning pole Saturday was a record-extending 79th.

"It's so hard to overtake here," Hamilton said. "So positioning is everything."Vettel tried to make ground, almost bumping into Verstappen as they headed into the first corner on Sunday. They just avoided contact.

Moments later, Vettel passed Verstappen with a great move on Raffles boulevard while behind them Sergio Perez knocked his Force India teammate Esteban Ocon into the wall and out — bringing a safety car onto the track for four laps.

When the race re-started, Ferrari gambled on pitting first for new tires by bringing in Vettel first. Mercedes pitted Hamilton moments later, and when Vettel came back out he was still behind Hamilton and lost more time getting past Perez.

Verstappen was the next in, almost colliding again with Vettel into turn 3. Verstappen held position, Vettel dropping to third.

"No chance, we are again too late," Vettel complained over team radio, taking another apparent swipe at team strategy. "If (being aggressive) works it's great — today it didn't work by quite a bit."Time is running out for Vettel, who realistically has to win in Russia in two weeks' time if he is to get back into title contention.