Defending double world champion Max Verstappen extended his lead in this year's title race when he drove his Red Bull to a comprehensive victory in challenging conditions in Sunday's Monaco Grand Prix.

The 25-year-old Dutchman, driving with controlled aplomb in conditions that changed from warm sunshine to a downpour, came home 27 seconds clear of Aston Martin's two-time world champion Fernando Alonso. 

It was his second victory on the barrier-lined streets of the Mediterranean principality in three years, his fourth win this year and the 39th of his clear, stretching his lead ahead of Red Bull team-mate Sergio Perez to 39 points in the championship. 

Esteban Ocon finished a popular third for Alpine to become the first Frenchman to claim a Monaco podium since Olivier Panis won in 1996.

"That wasn't easy," said Verstappen. "It was quite a difficult one! I didn't want to go long on my first stint, but I had to stay out when the rain came down and then it was very tricky to drive. 

"It was incredibly slippery and quite difficult," he said. "I clipped the walls a few times, but that's Monaco. It's nice to win and super-nice to win in this weather!"

Alonso secured his fifth podium finish in six races this year. 

"It was difficult," the Spaniard said. "Max drove super-well on the medium tyres in his first stint and it was complicated out there in the rain. I think everyone did an amazing job to stay on the track."

Ocon's success came in Alpine's 50th Grand Prix and after some recent strife in the team. 

"A super weekend," he said. "We didn't make any mistakes and I am enjoying this and hope it is the first of many." 

Ocon held off a late attack from seven-time champion Lewis Hamilton who finished fourth ahead of his Mercedes team-mate George Russell, local hero Charles Leclerc of Ferrari and Pierre Gasly in the second Alpine. 

Carlos Sainz finished a frustrated eighth in the second Ferrari ahead of the McLaren duo of Lando Norris and Oscar Piastri. 

The race began in beautiful conditions with an air temperature of 26 degrees Celsius and the track at 47 degrees, but with rain forecast. 

Alonso made a vibrant start, but it was not enough to unsettle Verstappen who pulled clear in the dash to Saint Devote where the grid order remained unchanged.

Hamilton was sandwiched between the Ferraris of Sainz and Leclerc, who had taken a three-place grid penalty for blocking Lando Norris in qualifying. 

Perez, who started from the back after crashing out in qualifying, made an immediate stop for hard tyres while Verstappen, on mediums, pulled away to lead Alonso, on hards, by five seconds by lap 15. 

- 'Pretty dangerous out here' -

Sainz made early attempts to pass Ocon's Alpine and in one move he clipped the Frenchman's car, damaging his front wing. 

He stayed out despite instructions to pit.

Verstappen extended his advantage to 8.4 seconds by lap 20 and 10.6 by lap 22 when dark clouds loomed. 

Alarmed by tyre-wear, Verstappen warned his crew. 

"Front left really isn't pretty," he said, as he approached a thicket of traffic that included Perez, in 16th. 

Hamilton pitted on lap 32 for 'hards', re-joining eighth behind Russell while a frustrated Verstappen saw his lead trimmed to 7.9 seconds. 

Ocon and Sainz soon followed into the pits while the Dutchman stayed out. 

"It's almost undriveable," he grumbled, but was told to stay out as a stop would cost him the lead. 

Perez continued his incident-plagued weekend when he hit the back of Kevin Magnussen's Haas and damaged a front wing. Perez pitted for a new one and fresh mediums returning in last place. 

By lap 45, as other drivers pitted the front two were more than 30 seconds clear of the rest.

By lap 52, it was raining. 

In the sudden treacherous localised conditions, the drivers tip-toed to survive, or gambled. 

Alonso pitted for mediums but had to come in to change again as the rain intensified. Verstappen came in for intermediates and Alonso returned to do the same. 

Ten minutes of chaos ensued. Magnussen and Logan Sargeant of Williams both crashed.

"It's getting to a point where it's pretty dangerous out here," reported Hamilton, who was in close pursuit of Ocon for third and equalling Ayrton Senna's record of eight Monaco podium finish. 

As the rain relented, with ten laps to go, the order was unchanged. Verstappen led by 24 seconds with Alonso second 15 clear of Ocon and resisting Hamilton over the final dash to the flag.

pb/ea