Red Bull’s Max Verstappen survived a mid-race downpour to win the Monaco Grand Prix from Aston Martin’s Fernando Alonso.

And Aston Martin appeared to miss a chance to beat Verstappen by pitting Alonso for a set of dry tyres as the rain was intensifying.

Had Alonso been given treaded tyres, his stop – while Verstappen was still on untreaded slicks – looked as if it might have led to the Spaniard taking the lead.

But Alonso had to stop again for intermediate tyres on the following lap, when Verstappen did the same, and any victory chances were gone.

Verstappen’s win, his fourth in six races this year, moved him 39 points clear of team-mate Sergio Perez in the championship.

The Mexican had a nightmare race after starting from the back following his crash in qualifying and finished down in 17th place.

Rain causes chaos

The rain started lightly on lap 51 and intensified slowly over the next few laps, but the fact it was initially largely over the section from Casino Square to the tunnel made decisions as to tyre choices difficult.

By lap 54, with 24 to go, half of the track was wet and half dry, and Verstappen leading from Alonso, Mercedes’ George Russell, Alpine’s Esteban Ocon, Ferrari’s Carlos Sainz, Mercedes’ Lewis Hamilton and Ferrari’s Charles Leclerc.

Verstappen had been hanging on with his fading medium tyres much longer than he wanted as Red Bull waited for the rain, while Alonso behind him on hard tyres was more comfortable but 13 seconds adrift.

Aston Martin chose that lap to pit Alonso, but they fitted medium, untreaded slick tyres, rather than the treaded intermediates that Russell, Hamilton, Ocon and the other Alpine of Pierre Gasly all chose when they pitted 30 seconds or so later.

Verstappen and the Ferrari drivers stayed out, but the intensifying rain led to the Dutchman hitting the wall at Portier and Sainz spinning at Mirabeau.

Had Alonso been on intermediates, it looked as if might have had a chance to make up enough time to pass Verstappen when the Red Bull driver pitted the next time around, although a quick analysis of the lap times suggested he probably would not have made it.

Red Bull team principal Christian Horner said Verstappen always had “enough margin” to pit and still retain the lead if Alonso had fitted intermediates.

Alonso said that when he pitted most of the track was dry apart from Turns Five, Six and Seven and the team believed the shower would be short.

As it turned out, the rain grew heavier and both had to pit on lap 55 to fit intermediates and Verstappen retained the lead.

Alonso’s advantage over the rest of the leading runners, all of whom had pitted other than Russell, ensured he maintained second place, while Ocon vaulted back into the third place he had held from the start but lost as the pit-stop period started before the rain developed.

Alonso closed on Verstappen quite quickly in the first laps after changing tyres, cutting his advantage by five seconds in as many laps while also lapping seconds faster than any other driver in the field.

But Verstappen then began to edge away again and controlled the race to the end.

More questions for Ferrari’s strategists

Ocon was left holding off Hamilton and Russell, which he did with aplomb to the end of the race, for his and Alpine’s first podium of the season after a difficult start to the year littered with errors that earned the team a public dressing down from chief executive officer Laurent Rossi at the last race in Miami.

The few laps when the rain first came down were hectic, with cars sliding all over the place, and Russell was one of the drivers to lose out – he said he locked up and slid down the escape road, in a mistake not caught by the TV cameras, which he said cost him third place.

Ferrari lost out by delaying their pit stops a lap longer than Verstappen and Alonso and Leclerc and Sainz dropped down to sixth and eighth.

It was the second questionable strategic decision they had made during the race, having pitted Sainz against his wishes early for a driver running hard tyres and cost him the chance of trying to pass Ocon.

Sainz raged on the radio afterwards, telling them that it was exactly what he had warned them about not doing, and he finished a disappointing eighth, also losing out to Gasly.

McLaren’s Lando Norris and Oscar Piastri completed the points positions in ninth and 10th places.

Perez’s title hopes fade

Red Bull chose an inventive strategy for Perez, pitting him for hard tyres after just one lap and planning to run to the end on them and gain when others pitted.

But after making brief progress, the move left him stuck behind Aston Martin’s Lance Stroll and his frustration grew.

When Verstappen came up to lap them on lap 33, Perez sought to take advantage too.

He tried an overtaking move on the outside of the harbour front chicane that was never on and he had to give the place back.

His race unravelled from there. Two laps later, he hit the back of Kevin Magnussen’s Haas and broke his front wing, requiring another pit stop.

He also crashed during the rain late in the race and made a total of five pit stops for a race to forget which surely ends his championship hopes.

Whilst they were always slim, which he was convincing himself he could keep them alive for much longer than six races into the season.