MONTE CARLO, Monaco - Mercedes' Lewis Hamilton and Nico Rosberg, after dominating the first five races of the 2014 Formula 1 season with consecutive 1-2 finishes, might not have it all their own way on the narrow of streets of Monaco on Sunday (May 25).If the sound of Mercedes' rivals clutching at straws has become more audible - unlike the race cars - a flutter on a different winner might be a better bet than many placed in the city's famous casino this weekend.Ferrari's Fernando Alonso told reporters after the 2014 Spanish GP in which Hamilton scored his fourth win in a row for the German automaker with team mate Rosberg second: "I think Monte Carlo will be one of the few opportunities to challenge Mercedes, especially for Red Bull."Through the corners Red Bull is very fast. On the straights its cars seem to lose a lot of lap time. In Monte Carlo there are no straights so maybe Red Bull could challenge Mercedes... we'll see."UNFORGIVING BARRIERSAlonso has won twice in Monaco, once for Renault and once for McLaren, so would become the first driver to win the most glamorous race on the calendar for three teams.Monaco, its streets lined by unforgiving metal fences, might be a processional race with little overtaking but it can never be predictable. Fickle weather and the ever-present risk of collision and pace-car periods sees to that.However Ferrari has not threaded its way to victory in 2014's most alluring race since Michael Schumacher's triumph in 2001.Red Bull, with Daniel Ricciardo and four-times champion Sebastian Vettel third and fourth at the previous race in Spain, seem to be picking up speed.Mercedes motorsport head Toto Wolff admitted: "They are still the benchmark. The power unit (in Monaco) is not so important. Monaco is always different and I guess there is a team that clearly has an advantage and probably on a street circuit such as Monaco everything can be different."History supports that: On the previous 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. HAMILTON’S WINNING STREAKIn 2014 it may just be Hamilton's rather than Mercedes' winning streak that comes to an end as the championship-leading Briton chases his fifth chequered flag in a row.Rosberg won from pole in 2013 and grew up in the principality. He 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 (Hamilton) in Spain.Rosberg said: "To re-gain the advantage at my home race would be fantastic. I'll be pushing harder than ever to make it happen."It is also a Hamilton favourite, another Monaco resident and winner for McLaren in 2008when he took the championship. He said: "I honestly never expected I'd win four consecutive GP's in my career and I'd love to continue that run here."Red Bull has won in Monaco three times in four years, twice with now departed Mark Webber whose successor and compatriot Ricciardo is rarin' to go.‘TOUGHEST RACE OF SEASON’If racing around Monaco is, as three-times 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."The new V6 turbo-hybrid engines, with more torque and so more wheelspin, also threaten to liven things up with drivers likely to be more on the ragged edge than ever, as Felipe Massa observed:"I think Monaco will be a very, very difficult race. We drive with the car a lot more sideways. The torque we have from the engine is maybe double which to crash."I think it will be the toughest race of the season."Stay with Wheels24 for the 2014 Monaco GP weekend!