World champion Lewis Hamilton ended his six-months wait for a win on Sunday when he secured an unexpected and skilful victory for Mercedes in an incident-filled Monaco Grand Prix.
Taking full advantage of a bungled pit stop for his nearest rival, Australian Daniel Ricciardo of Red Bull, Hamilton drove supremely in mixed conditions to seize his first triumph in nine races since clinching his third title at the 2015 United States Grand Prix last October.
Ricciardo, who started from his maiden pole position, led until he pitted for slick tyres - that were not ready for him -- after 32 laps and finally came home second, 7.2 seconds behind the three-time champion.
It was Hamilton's second win on the famous Mediterranean street circuit, his first this season and the 44th of his career. It also repeated his 2008 triumph when he started third and won in wet conditions.
Mexican Sergio Perez finished third, 6.5 seconds behind a disconsolate Ricciardo, but ahead of four-time champion Sebastian Vettel of Germany (Ferrari) and two-time champion Fernando Alonso of Spain, who finished a superb fifth for McLaren on the 50th anniversary of their Formula One debut race in 1966.
Hamilton's win kept alive his title defence and, with Rosberg off the podium, trimmed the leader's advantage to 24 points, less than a single victory, in the title race.
"Thank God that today went as I'd hoped," said Hamilton, who sopped to give Justin Bieber a swig of his champagne in the podium celebrations.
"A big thank you to the team. I'm kind of lost for words. I prayed for a day like this and it came through so I feel blessed. That was the longest run after I stopped for those tyres."
A furious Ricciardo struggled to control his feelings and his language. "I don't even want to comment on the race," he said. "Two weekends in a row now, I've been screwed. It sucks. It hurts."
On a grim afternoon of torrential rain in the Principality, the race started -- for the first time -- behind a Safety Car with the entire field running on full-wet tyres.
This negated any advantage that Ricciardo could have gained by Red Bull's choice of 'super-soft' tyres for final qualifying on Saturday.
Finally, on lap seven, the Safety Car came in and the contest began in earnest.
Almost immediately, Kevin Magnussen pitted for intermediate tyres and his Renault team-mate Briton Jolyon Palmer wrecked the front of his car on his way down the straight as he lost grip on a pedestrian crossing and slid into the barriers at Ste Devote.
A Virtual Safety Car (VSC) was deployed until lap 11 when racing resumed and Kimi Raikkonen promptly crashed his Ferrari at Loews, almost collecting Romain Grosjean with him.
On lap 16, Hamilton finally passed Rosberg on the run uphill from Ste Devote - the German appearing to succumb to team orders - and swiftly began his pursuit of Ricciardo.
The pair traded fastest laps, but the Englishman, who won in the Monegasque rain in 2008, had 13 seconds to make up.
After 20 laps, Ricciardo was 12.8 seconds ahead. Rosberg pitted for 'intermediates' and dropped to fifth.
Ricciardo pitted - in 3.6 seconds - after 23 laps, handing the lead to Hamilton who unexpectedly stayed out. This meant the defending champion was the only driver in the top 12 on wet tyres as the sun broke through.
Planning a switch to slicks, Hamilton resisted Ricciardo's attacks as the circuit dried and he extended his lead over Rosberg in third.
Hamilton finally pitted after 31 laps for a set of 'ultra-softs', followed by Rosberg and Vettel, the Ferrari man advancing by emerging first.
Ricciardo stayed out for a lap before following suit to find his crew running around for a set of 'super soft' tyres. As he rejoined, Hamilton swept into the lead.
The Australian was more confident than Hamilton on his slick tyres, at that stage, before another VSC period when, after Magnussen hit the barriers at Mirabeau, Max Verstappen crashed heavily at Massenet.
On resumption, Ricciardo attacked, and failed to pass Hamilton, who 'closed the door' at Tabac. His hand gestures - and some profanities - confirmed his frustration and anger.
A stewards inquiry resulted in 'no further action' as the pair diced for the lead before another VSC pause when the squabbling Saubers, ignoring team orders, collided at Rascasse.
Having led only one lap this year, prior to the Monaco race, Hamilton revelled in demonstrating his mastery at the front, defending his position with aplomb to Ricciardo's frustration.