The Red Bull Racing driver led all 78 laps to win for the seventh time in his career from Sebastian Vettel and Lewis Hamilton
Monaco Grand Prix: Daniel Ricciardo survives engine drama to win in Monte Carlo
"Redemption" was how an emotional Daniel Ricciardo used to describe winning the Monaco Grand Prix for the first time.
Two years ago on the same weekend in the Principality the Australian had shown Formula One that he was more than just a smiling face.
Back then he had been denied a win by a bungled pit stop by his Red Bull Racing team. He could not hide his devastation post-race.
So standing on the top step of the podium was always going to be an especially sweet moment, the seventh win of his F1 career coming at the one that had got away before.
Redemption sums up a tough past four weeks for Ricciardo. After colliding with teammate Max Verstappen four weeks ago in Azerbaijan, he had spun on his way to an underwhelming fifth place in Spain.
But in Monaco he was superb. He did not put a wheel wrong all weekend. Not easy at Monte Carlo were the proximity of the barriers around the track can easily lead to a costly mistake.
Just ask Verstappen. His crash in Saturday's final practice not only damaged his car and prevented him from taking part in qualifying, it wrecked his weekend. He started last on the grid, and despite being the fastest car at the track had to be content with ninth place.
In contrast, Ricciardo had the perfect weekend. He was fastest in every practice session, took pole and then led all 78 laps to prevail for the second time this season after his win in China in April.
But that does not tell the whole story. Mid-race he complained of a loss of engine power. Christian Horner, the Red Bull team principal, estimated that the issue cost the 28 year old around 25 per cent of the power in the RB14's Renault unit.
Horner said initially the team feared they were going to have to retire the car, but Ricciardo drove around the problem despite having Sebastian Vettel's Ferrari less than a second behind him for most of the race.
A relieved Ricciardo said in his post-race podium interview: "We had problems, a lot to deal with and before halfway I felt a loss of power and thought the race was done.
"We got home using just six gears, but we got it home and I'm stoked. There were a few doubts that came in mid-race, but we won Monaco - it feels good."
It is unlikely that if Ricciardo had suffered the issue at any other track he would have held on to win. Monaco has always been a difficult place to overtake on, unless you have a sizeable performance advantage on the car ahead.
Vettel was unable to find a way past his former teammate and in the end had to be content with second spot, easing off himself in the closing laps to deal with his heavily worn tyres.
World championship leader Lewis Hamilton, who had won the previous two races in Monaco, was third as Vettel, his nearest rival in the drivers' standings, cut his title advantage to 14 points. The four-time world champion Hamilton will be happy with that; Mercedes were the third fastest package on a track that has not suited them in recent years.
The second Ferrari of Kimi Raikkonen was fourth, ahead of the Mercedes of Valtteri Bottas, with the top five finishing in the order in which they started.
Esteban Ocon was the best of the rest in sixth, ahead of Pierre Gasly's Toro Rosso and the Renault of Nico Hulkenberg.
Verstappen proved overtaking was possible as he came up from last on the grid to earn two points for ninth, with the second Renault of Carlos Sainz completing the top 10.
Ricciardo and Red Bull may find it tough to repeat their success at the next round in Canada on June 10, the long straights at Circuit Gilles Villeneuve in Montreal will suit Mercedes and Ferrari better.
But Ricciardo's victory in Monte Carlo was an important reminder, with the Australian out of contract at Red Bull at the end of the season, of what he can do when given the opportunity to race at the front.