Mercedes admits Red Bull threat in Monaco

May 27 (GMM) After Max Verstappen's surprise win in Barcelona, Red Bull appears poised to complete a back-to-back upset this weekend in Monaco.

With Renault's much improved engine in the rear of his car, Daniel Ricciardo was so far clear of the field in Thursday practice that most are assuming the Australian is the man to beat in the twisty Principality.

That is even despite the fact that Mercedes normally 'turn up' the power of their turbo V6 engines on a Saturday.

"It's not six tenths that we get out of it," said championship leader Nico Rosberg, "so it's a big surprise how fast they are.

"We can improve the car," the German added, "but whether it will be enough - I don't know."

Teammate Lewis Hamilton agrees, telling the Spanish broadcaster Movistar: "The engines don't make much difference here and we knew they (Red Bull) had a good car.

"But did I expect them to be this fast? No," said the reigning world champion.

There are not many who disagree. When asked who he would tip for a five euro bet, McLaren's Jenson Button answered: "Daniel Ricciardo.

"The Merc is a very good car but the Red Bull can match it and this circuit isn't so dependent on outright power," he added.

"It's the best chance they have got of winning again this year."

Sebastian Vettel, meanwhile, had a very bad day on Thursday, hitting the wall twice, but he said that's no reason to write Ferrari off.

But he also acknowledged Ricciardo's pace.

"My guess is they will also be strong in qualifying, and here qualifying is almost half the race win," said Vettel.