Sergio Perez took a remarkable debut Formula One win in Sunday's Sakhir Grand Prix in Bahrain after Mercedes fumbled what should have been a first victory for George Russell.

Standing in for Lewis Hamilton after the world champion tested positive for COVID-19, Russell took the lead from teammate Valtteri Bottas at the start and seemed set for a fairy-tale debut triumph.

But things started to unravel for Mercedes when the safety car was deployed on lap 61 after debutant Jack Aitken - himself replacing Russell at Williams - lost his front wing after a spin.

With a sizeable gap to the rest of the field, Mercedes called both drivers in for a precautionary pit stop, but put a wrong mix of tyres on Russell's car before realizing their mistake halfway through Bottas' stop.

This meant Russell had to pit again the following lap to fit a correct set, while Bottas was sent back out on his original rubber after an agonizing 27-second wait.

The two Mercedes were now fourth and fifth, with Bottas ahead, but the subsequent bunching of the pack meant all hopes of victory were not yet lost, and Russell took advantage of his fresher rubber to move quickly up into second place behind new leader Perez.

Alas for the Briton, a slow puncture saw him back in the pits again on lap 79 for yet more new tyres, dropping him out of contention and allowing Perez to cruise home for a remarkable win.

"I am a little bit speechless. I hope I am not dreaming because I dream so many years being at this moment - 10 years it took me, I don't know what to say," said Perez, who had to pit on lap 1 after being hit by the Ferrari of Charles Leclerc, but carved his way through the field to sit third before the Mercedes hit trouble.

"After the start I thought the race was again gone but it was all about not giving up and recovering. The luck has not been with us this year, but we won the race on merit," added the Mexican, who remains without an F1 drive for 2021 and has been linked with Alex Albon's seat at Red Bull.

Behind Perez, Renault's Esteban Ocon took a career-best second place ahead of Perez's teammate Lance Stroll. Carlos Sainz took fourth for McLaren, with Daniel Ricciardo fifth in his Renault.

Alex Albon finished an underwhelming sixth and must be looking nervously over his shoulder as the clamour grows for Perez to take his seat next year, while Daniil Kvyat took seventh for AlphaTauri in what looks to be his last year in F1.

Bottas slumped to eighth in the final standings after struggling on his older tyres, just ahead of a frustrated Russell, whose bonus point for fastest lap will be scant consolation for losing a shot at victory. Sainz's teammate Lando Norris rounded out the top ten.

Drivers who failed to finish included Leclerc, who retired after tagging Perez on lap 1, and Red Bull's Max Verstappen, who slid into the wall in the ensuing confusion. Nicholas Latifi was the only other driver not to see the chequered flag, retiring his Williams with an oil leak.

In the points standings, the absent Hamilton remains on 332 points, with Bottas still second on 205 points and Verstappen third on 189. In the constructors' championship, Mercedes have 540 points, Red Bull stay second with 282, while Perez's win helps Racing Point into third place on 194 points.

The next and final round of the 2020 F1 season is the Abu Dhabi Grand Prix on December 13 at the Yas Marina Circuit.