After being tight-lipped during the race, Red Bull have now revealed what almost caused Daniel Ricciardo to retire from the Monaco GP on Sunday.The Australian had looked peerless throughout the weekend in Monte Carlo but was faced with a massive challenge simply to make the finish after reporting a loss of power during the race.It would allow Sebastian Vettel to close up in second but ultimately, his own problems with tyres and the speed of the RB14 through the corners meant the German could never seriously threaten to steal the victory.Figures through the speed trap on the main straight suggested Ricciardo's car was some 20kph slower than the Ferrari, usually about the number that would be expected with an ERS failure.Deciding not to answer enquiries from Sky Sports' Ted Kravitz as to whether that was the case while the cars were on track, team boss Christian Horner eventually admitted later it was."He has lost about 25% of the power of the engine," he told the British broadcaster."Then because of the way these engines work, his rear brake temperatures are going through the roof. We saw it with Lewis Hamilton and Nico Rosberg a few years back in Montreal."Horner would then explain how Ricciardo was coping with the issue and praised the way he did so under such pressure."He is having to cool the brakes, he is having to cool the car, he is having to lift off to do that," he said."He is having Sebastian Vettel breathing down his neck. He cannot make a mistake. He cannot lock a wheel up."He is dealing with all the switch changes and all the stuff that he has got to manage. And he totally nailed it. He was the coolest guy out there today."Without the ERS or the MGU-K part which deploys the energy, a driver is missing around 160 horsepower from a car which in race mode is likely producing between 850-900hp.Also, because much of that energy comes from engine braking, when the MGU-K fails, it puts a great deal of extra stress through the rear brakes which causes them to overheat and sometimes fail, as they did with Hamilton in Canada in 2014.With such a large deficit of power, Ricciardo said he was only reaching sixth gear on an eight-gear transmission and also revealed the first thoughts that went through his head when the problem began."I expected my race to be over in a few corners," he claimed. "After a few laps I was stressing out and the team said 'this is you for the rest of the race now'."I still don't really know how we did it, obviously it helps that the track's so difficult to overtake."That was not a good feeling and I couldn't really enjoy much of the race after that."

Horner also admitted the decision to continue went against the advice he was being given by the engineers back in Milton Keynes.

"It was unbelievable," Horner added. "He [Ricciardo] was not going to give this race up, this weekend. He has been quickest in every session.

"They are telling me on the intercom that we are going to have to retire the car after one or two laps, and I said look, we are in the lead of the Monaco GP, we are keeping going."

And thank goodness Red Bull did as Ricciardo finally put the sense of injustice after his loss in 2016 to rest and now sits just 38 points behind championship leader Hamilton with 15 races still to go.