The Red Bull driver led from start to finish, but as early as Lap 19 suffered a loss of power from his energy recovery system that allowed Sebastian Vettel's Ferrari to close in on the back of his car. A series of switch changes on Ricciardo's steering wheel helped manage the issue, while Vettel also suffered his own problems when his steering wheel display went blank on Lap 39.

Despite the loss of power, Ricciardo maintained a one-second lead over the Ferrari for the majority of the race -- safe in the knowledge that the car behind requires a significant pace advantage to make an overtaking move stick at Monaco. A late virtual safety car to clear debris from a collision between Charles Leclerc and Brendon Hartley worked in Ricciardo's favour and gave him a five-second buffer over Vettel for the final four laps.

The victory is Ricciardo's second of the season but his first at Monaco -- and all the more significant after he missed out on a win here in 2016 due to a botched pit stop. After taking the chequered flag at the end of the race, Ricciardo sounded exasperated on the team radio before uttering the word "redemption" -- summing up the importance of the victory to the Australian.

Lewis Hamilton retains the championship lead leaving Monaco after finishing a solid third behind Vettel. Ricciardo's issues allowed the Mercedes to close in on the top two midway through the race, but tyre troubles meant he never got close enough to attempt an overtaking move. Kimi Raikkonen secured fourth, 0.695 seconds ahead of Valtteri Bottas in fifth, who in turn had Esteban Ocon not far behind him in sixth.

From 10th on the grid, Pierre Gasly took seventh for Toro Rosso after Fernando Alonso's McLaren retired ahead of him with a gearbox issue on Lap 53. Gasly had to hold off Nico Hulkenberg at the end of the race, who used an alternative strategy to go from 11th on the grid to eighth at the finish and attack at the end of the race on hyper-soft tyres. The second Red Bull of Max Verstappen used a similar strategy to go from last on the grid to ninth at the finish, but he will still be ruing his accident in final practice, which damaged his car beyond repair ahead of qualifying and forced him to start from the back of the grid. Carlos Sainz took the final point on offer in the second Renault.

How the race unfolded

Daniel Ricciardo celebrates a gutsy victory in Sunday's Monaco Grand Prix. Dan Istitene/Getty Images

After Ricciardo held off Vettel into the first corner, it seemed most of the hard work had been done. It became clear in the opening stint that he had the faster car, and once he built a two-second buffer on Vettel it looked as though he would control the race from the front.

Hamilton, in third place, kicked off the pit stops on Lap 12 but filtered back onto the track behind Ocon and lost any advantage from an undercut. Vettel followed suit with a pit stop on Lap 16 and retained a good margin over the Mercedes before Ricciardo made his single stop on Lap 17. With both the race start and his pit stop going smoothly, Ricciardo should have been set for an easy victory, but within a lap he felt a loss of power as his car's MGU-K -- the part of the hybrid system that supplies electrical energy to the rear wheels -- cut out.

In that moment Ricciardo believed his race was over, but a series of setting changes helped keep the power unit operational -- albeit roughly 160bhp down on power. Vettel smelled blood and quickly closed in on the gearbox of the Red Bull around the 3.3-kilometre track. He got close but there were already signs of graining on his front left tyre, and that severely damaged his chances of getting a good run onto one of Monaco's short straights to attempt an overtaking manoeuvre.

On Lap 39, Vettel's issues got momentarily worse as he suffered a blackout on his steering wheel display. The display eventually came back, but the tyre problems persisted and it soon became clear that only a mistake from the car in front would result in an overtaking opportunity. That was entirely possible given the problems Ricciardo was facing, but despite being restricted to just six gears, the Red Bull driver held everything together.

"We had problems," Ricciardo said after the race. "I don't know how much of the radio was broadcast, but we had a lot to deal with during the race. Before the half way, I felt a loss of power and I thought the race was done. We got home just using six gears.

"Thanks to the team, we got it back. So I'm stoked. There was a few doubts that came in midrace. We won Monaco so ... it feels good. Thanks everyone for the support. A lot of Aussie flags on the in lap."

One last twist came five laps from the end, when Leclerc, in 12th, suffered a front-left brake failure and piled into the back of Hartley's Toro Rosso at the Nouvelle Chicane. The incident left debris scattered across the braking zone, but the marshals were able to clear the pieces of carbon fibre under a virtual safety car, meaning a full safety car -- which would have allowed Vettel to close on the back of Ricciardo -- was not required.

Vettel was further disadvantaged by the VSC when Stoffel Vandoorne emerged from a pit stop directly ahead of him and slowed the Ferrari just before racing resumed and the track went green. That gave Ricciardo a comfortable buffer to the end of the race, and he nursed his car across the line to take a memorable victory on the streets of Monaco.

The win moves Ricciardo up to third in the standings on 72 points, but he is 24 shy of Vettel and 38 off Hamilton, who leads the way on 110.