1. Fernando Alonso (Aston Martin) - 1:31.116

2. Charles Leclerc (Ferrari) +0.150

3. Max Verstappen (Red Bull) +0.276

4. Lewis Hamilton (Ferrari) +0.364

5. Oscar Piastri (McLaren) +0.355

It's only by a smidge, but Fernando Alonso's quickest time now is a 1:31.116, which is nearly two seconds faster than his Aston Martin team-mate Lance Stroll, who is down in 18th place.

Gabriel Bortoleto is one spot higher than Stroll but the Brazilian peppers the radio with some blue language after finding traffic on the Singapore street track.

Williams have kept Carlos Sainz on the medium tyre for now, while Mercedes have also held back on fitting the soft compound in this session. Max Verstappen, meanwhile, has ditched his softs and is now ploughing on with some hard running to round out this hour of practice.

The track is ramping up with each lap, so the times are tumbling. Aston Martin have joined the pack on the C5 soft compound and Fernando Alonso leapfrogs his rivals to go quickest with a 1:31.117. The two-time world champion's marker is 0.149 seconds better than the Ferrari of Charles Leclerc.

Image source, Getty Images

Isack Hadjar in the Racing Bulls puts in another good lap to move to fourth on the timesheets as the Red Bull of Max Verstappen goes to within 0.126 seconds of Charles Leclerc's best time to go into second.

Oscar Piastri now sits third, pushing team-mate Lando Norris down the order, but the Australian is not happy with the slow-moving car of Lewis Hamilton. "Ferrari will invent mirrors one day, I hope," he says on the team radio.

Image source, Getty Images

Image source, Getty Images

Oscar Piastri knows he can't afford to have another disappointing weekend like Azerbaijan when chasing down his maiden F1 world championship.

With his title lead down to 25 points, Piastri, who has won seven grands prix this season and finished third in Singapore last year, said there was "some tough lessons to take" from his bruising experience of crashing in both qualifying and the race - plus a jump start - a fortnight ago.

"Baku was quite a good reminder of firstly how quickly everything can change but also on some of the things that have made the season so successful for myself and the team," said Piastri on Thursday.

"So I think just trying to stay focused on that will naturally take care of the championship picture."

Piastri is on the radio to say his car is "very understeery" and his lap on the softs only offers up a P6 spot on the board.

Does Charles Leclerc think Ferrari can win one of the remaining races of the season? Unfortunately, the Monegasque driver isn't confident the Scuderia have the pace to compete with the McLarens and challenge for champange moments in 2025. For now, though, he'll have to settle for sitting top of the timesheets on the soft tyres with a 1:31.266 - over four-tenths quicker than Lando Norris in the papaya car on the same compound.

Image source, Reuters

Rebecca Clancy
F1 journalist on BBC Radio 5 Sports Extra

Carlos Sainz is on an absolute high. This track is very different to where we've come from - it's high downforce and slow corners and it's really an enormous challenge. I would expect someone like Sainz with all his experience and talent to go pretty well here.

The soft tyres are starting to make an appearance but Williams, like Aston Martin, have fitted Carlos Sainz with a set of the yellow medium rubber. The Spaniard will surely stil be on high after his first podium for the team last time out, and now he's beaten Fernando Alonso's time with a 1:31.812.

Over at Mercedes, Kimi Antonelli suffers a massive snap of oversteer at Turn One and informs his pit wall of his bid "slide".

Aston Martin team principal Andy Cowell is chatting to Sky Sports on the pit wall and says Singapore's "unforgiving" blend of tight and twisty sections with flat-out blasts "suits our characteristics more", which is good, as Fernando Alonso has just gone back to the top of the timesheets on the mediums with a 1:32.054.

Isack Hadjar has got the key of the door now - he turned the big 21 last Sunday and celebrated with a trip to Tokyo. Lovely. The Racing Bulls rookie is another hard runner in this first practice session and after banking a purple sector in the opening part of the lap, the Frenchman has lifted himself up to third place on the timesheets.

Image source, Lewis Hamilton X

It's been a tough week for Lewis Hamilton in the build up to Singapore, as the seven-time world champion announced the death of his beloved dog, Roscoe, on Monday.

The 12-year-old bulldog, who was adopted by Hamilton in 2013, was put to sleep last Sunday and died in the Ferrari driver's arms after being admitted to hospital with pneumonia.

"It's been amazing to see the support from so many people around the world," said Hamilton on Thursday, "just overwhelming to see how much Roscoe meant to people, and the kind messages I've received have been really uplifting, so I'm really grateful for that.

"I read somewhere that grief is the last act of love, I think, and I'm definitely feeling that."

1. Lando Norris (McLaren) - 1:32.493

2. Max Verstappen (Red Bull) +0.021

3. Fernando Alonso (Aston Martin) +0.099 - medium tyre

4. Charles Leclerc (Ferrari) +0.107

5. Lewis Hamilton (Ferrari) +0.541

Williams have confirmed Alex Albon will take no further part in first practice following the rear brake fire but they are hoping the issue will be fixed so he can be back up and running for second practice later on.

Aston Martin have opted to run the medium compound early doors at Marina Bay. Fernando Alonso couldn't bring any points home from Azerbaijan last time out but can the higher downforce nature of the Singapore circuit suit the team better? The Spaniard is now leading the field with a time of 1:32.592, which is over four-tenths faster than the second quickest driver, Max Verstappen.

Carlos Sainz, the only Williams out on track for now, beats Lando Norris' quickest time, on the same tyre, with a 1:33.325. That time is scrubbed out, though, as title leader Oscar Piastri climbs to the top of the timesheets with a 1:33.239.

As Williams try and tackle the brake fire with multiple fire extinguishers, out on track, Lando Norris is the quickest driver so far with a 1:33.388 on the hard tyre.

This is not the start Williams - and Alex Albon - would've wanted, especially after the team's joy at team-mate Carlos Sainz's podium finish in Azerbaijan. The car is in the pit lane and still burning, and there is a lot of activity around the rear of the car.

The mechanics are desperately trying to put out this brake fire as Alex Albon is still sitting in the cockpit. The Thai-Brit driver is safely climbing out of the car now. This all happened as Albon returned to the pit lane, and he was the one to flag to his team over the radio there was a fire.