Nico Rosberg Will Pose a Big Test for Lewis Hamilton: Bernie Ecclestone

Nico Rosberg has thrown down the gauntlet to Lewis Hamilton by winning his first race of 2015 in Spain and the German will make life tougher for the reigning champion at this weekend's Monaco Grand Prix, feels Formula 1 boss Bernie Ecclestone.

Rosberg beat Hamilton for the first time this season at Barcelona, putting him 20 points adrift of the Briton (111 points) after five races. (Nico Rosberg seeks rare Monaco hat-trick)

Ecclestone is backing Rosberg to challenge his Mercedes teammate consistently, more so on the streets of Monte Carlo on Sunday.

"He (Rosberg) is up for it (fight) for sure. I mean it is a case of he getting himself together. He proved that in Spain and I am sure he can do it again. He won in Monaco (last two years) so it will be a big test for him (Hamilton)," Ecclestone told PTI over the phone ahead of the most glamorous race of the season.

It should be a mouthwatering battle between the Mercedes drivers, keeping in mind the happenings of 2014 when Rosberg won the Monaco Grand Prix for the second time after taking a controversial pole position in qualifying, much to the dismay of Hamilton.

The title fight, too, is most likely to be contested between the Mercedes men again, even though Sebastian Vettel picked up a surprise win for Ferrari in Malaysia.

Fernando Alonso finds himself in unusual territory after moving to Honda-powered McLaren. The car looks far from scoring points as he languishes at 16th spot in the standings with teammate Jenson Button on 17th.

Does Ecclestone feel sorry for Alonso, who shifted to McLaren after five seasons at Ferrari?

"No, no. It is nothing like that. He (Alonso) has made a decision that suited him at that point of time so it is okay," added the British businessman.