Daniel Ricciardo recorded his second successive podium finish with a third place in Monaco, while Sebastian Vettel was cruelly denied a good result following a power unit problem that caused him to retire his RB10 in the early stages of the grand prix.
The race was won by Nico Rosberg, ending a four-race winning streak for Lewis Hamilton who trailed home behind his team-mate in second position. He was pushed hard in the final laps by Daniel. A tense battle saw the Australian catch and then harry the former World Champion in the closing stages as an eventful race received a grandstand finish.
Daniel had a poor start, dropping back from third to fifth. He was passed by Seb and Kimi Räikkönen, both of whom had good traction off the line from fourth and sixth respectively. The race wasn't given time to settle as a collision at Mirabeau between Sergio Pérez and Jenson Button saw the Mexican in the barriers and the Safety Car deployed. It stayed out until lap four but on the resumption Seb reported a loss of power. He continued around the lap, dropping back to last position and came into the pits. He rejoined a lap down but was unable to engage gears and had to retire.
"It's disappointing," said Seb. "I had a good start and then we lost boost pressure from the turbo, so I had no power and had to retire. The team did everything they could. I felt quite helpless in the car, so I was asking for an answer of what we could do, but there wasn't anything at that stage. We fixed some problems yesterday with the ERS, but some more came today with the turbo, but we will move forwards and it will be good for us soon."
While that was going on, Daniel Kyvat, running an excellent eighth on his Monaco debut, also retired, his Toro Rosso suffering an exhaust failure. Seb's technical issues promoted Daniel to fourth position, sandwiched between the Ferraris of Räikkönen and Fernando Alonso. Initially Räikkönen pulled out a lead but Daniel began to close the gap as the window for pit stops approached.
In recent years the strategy for Monaco has been a one-stop race. That might not necessarily be the quickest way around the Principality but with overtaking next-to impossible and track position at a premium it's seen as the only realistic choice. The front-runners, starting on a used Supersoft tyre, would have planned a stop around lap 30 of the 78, though their hand was forced when the Safety Car appeared on lap 26, following a crash at the Nouvelle Chicane for Adrian Sutil.
The front-runners all pitted – Mercedes had to stack but had enough of a gap to not lose track position. The driver who did lose-out during this period was Räikkönen. He had to pit for a second time following contact with a backmarker. That promoted Daniel to P3. Behind them in the pit stop frenzy, Jean-Eric Vergne nearly collided with McLaren's Kevin Magnussen and was given a drive-through penalty for the unsafe release.
The safety car pulled in at the end of lap 30 and the race resumed without incident. The two Mercedes pulled away from Daniel, who in turn built a gap to Alonso, now running fourth. The attrition rate got worse: Jean-Eric Vergne retired his Toro Rosso with an exhaust failure similar to the one that had halted Kvyat, Williams' Valtteri Bottas retired a smoking car, and Sauber's Esteban Gutiérrez tagged the barrier at Rascasse, spinning into the pit entry.
The real attention, however, was on Mercedes as they appeared to be readying for a pit stop. Then Hamilton began to fall away from Rosberg. Sensing an opportunity, Daniel picked up his pace and posted a string of fastest laps and personal bests, pushing his tyres to the limit – catching the Mercedes for over a second a lap. Hamilton, it transpired, was struggling with dirt in his eye. Eventually, he recovered some pace but spend the last few laps being hounded by Daniel.
"The race really came to life towards the end," said Daniel. "After the re-start we were just saving the tyres to the point that we could get to the end and then, with 20 laps to go, I thought they would be okay so I pushed. It was the first time in the whole race that I felt like I was really driving the car and we caught Lewis. It was fun but I couldn't get him, so I have to say the race finished better than it started."
That wasn't quite the end of the drama. Behind them Nico Hülkenberg in fifth place had been forced into a stint of 50-plus laps on the Supersoft tyre and was struggling at the end, with Magnussen closing fast. The Dane, however, suffered a power unit problem and began to fall back. He was passed by several cars but collided at the hairpin with the recovering Räikkönen. Both cars came to a stop but were able to get underway again – in Räikkönen's case back to the pits for a new front wing.
While the fallout from that was being digested, Rosberg calmly took the chequered flag for his second Monaco victory. Ten seconds later Hamilton and Daniel appeared and crossed line astern. Alonso was fourth, a further 20s back, Hülkenberg hung on to give Force India fifth, just ahead of Button. Felipe Massa was seventh for Williams, and Jules Bianchi crossed the line eighth. He was demoted to ninth after a penalty was applied but Marussia were in jubilant mood regardless: it was their first points finish. That promoted Romain Grosjean to eighth for Lotus, with Magnussen taking the final point.