MONACO - After dominating the first five races of the Formula One season, with four successive one-two finishes, Lewis Hamilton and Nico Rosberg may not have it all their own way on the streets of Monaco on Sunday.

If the sound of Mercedes' rivals clutching at straws has become more audible, unlike the cars, a flutter on a different winner could still be a better bet than many placed in the imposing casino this weekend. "I think Monte Carlo will be one of the few opportunities to challenge Mercedes, especially for Red Bull," Ferrari's Fernando Alonso told reporters after Spain where Hamilton chalked up his fourth win in a row for the German manufacturer with team mate Rosberg second.

"On the corners they (Red Bull) are very fast and on the straights they seem to lose a lot of lap time. In Monte Carlo there are no straights so maybe Red Bull could challenge Mercedes there. We'll see," said Alonso. Alonso has won twice in Monaco, once for Renault and once for McLaren, and would become the first driver to win the most glamorous race on the calendar with three separate teams.

Monaco, with its narrow streets ringed by unforgiving metal fences, may be a processional race with little overtaking but it can never be predictable. The fickle weather, and the ever-present risk of safety cars and collisions, sees to that. However Ferrari, the most glamorous team, have not threaded their way to victory in the year's most alluring race since Michael Schumacher's triumph in 2001.

Red Bull, with Australian Daniel Ricciardo and quadruple champion Sebastian Vettel third and fourth at the previous race in Spain, look to be picking up speed. "They are still the benchmark," recognised Mercedes motorsport head Toto Wolff. "The power unit (in Monaco) is not so important," said the Austrian. "Monaco is always different and I guess there is a team that has clearly an advantage at the moment and probably on a street circuit like Monaco everything can be different."

History backs that up: On the last three occasions that a team has started a season with five straight wins - Ferrari in 2004 and Williams in 1996 and 1992 - the run has bust in Monaco. This year, it may just be Hamilton's rather than Mercedes' winning streak that comes to an end as the championship-leading Briton chases his fifth in a row. Rosberg won from pole last year and grew up in the principality.

The German knows every kerb and corner, every turn and twist, from his boyhood journey from home to school and is determined to use that familiarity to good effect after falling three points behind his team mate in Spain. "To re-gain the advantage at my home race would be fantastic, so I'll be pushing harder than ever to make that happen," he said. It is also a favourite of the Briton, also a Monaco resident and winner with McLaren in 2008 when he took the championship.

"I honestly never expected I'd win four consecutive Grands Prix in my career and I'd love to continue that run here," said Hamilton. Red Bull have won Monaco three times in four years, twice with now departed Australian Mark Webber whose successor and compatriot Daniel Ricciardo is raring to go. If racing around Monaco is, as Brazilian triple champion Nelson Piquet once observed, like cycling around your living room then Ricciardo is up for it.

"When I was a kid I used to love riding my little bike around inside the house. It was more fun, there were more obstacles and a bit more danger. That really is what this is like," he said. The new V6 turbo hybrid engines, with more torque and wheelspin, also threaten to liven things up with drivers likely to be more on the ragged edge than ever. "I think Monaco will be a very, very difficult race," commented Brazilian Felipe Massa.

"We drive with the car a lot more sideways. The torque we have from the engine is maybe double what we had last year, and the grip from the tyre is not very high, so Monaco will be a very easy race to crash," added the Williams driver. I think it will be the toughest race of the season."