Gian Carlo Minardi says that Mercedes needs two Nico Rosbergs if it is to seriously challenge Red Bull, McLaren and Ferrari.

In the wake of the Singapore Grand Prix which saw Michael Schumacher leave his braking far too late, resulting in the elimination of himself and Jean-Eric Vergne from the race and a ten-place grid penalty for Japan, many have begun to question whether the time is right for the legendary German to retire (again).

Minardi, boss of the team which brought so many drivers into F1, not least Fernando Alonso, believes that Schumacher is standing in the way of his team's progress.

"(It was an) honest race for Rosberg who leads Mercedes towards the 5th place (in the Constructors' Championship)," he said. "This fact should give us pause. If the team had two Rosbergs, it could strive for the first four places.

"The reaction of the technicians toward Schumacher' mistake was meaningful," he added, referring to the scenes on the pit-wall in the aftermath of Schumacher's crash, "so I think it is time to change, even If Hamilton shift to Mercedes will be so difficult.

"Over the last three years, the McLaren team has been the one who got the greatest number of successes," he added. "If the three-pointed star team wants to improve, it will have to support Rosberg with a promising young driver (i.e. di Resta) or take a look around."

While clearly disappointed with Schumacher, Minardi was full of praise for some of his rivals.

"The weekend was in Hamilton's' hands, the only driver who was able to tackle the overwhelming power of the Red Bull's German driver. After tackling Vettel's supremacy, driving an amazing lap in qualifying, the Englishman was leading the race. If he hadn't had a hydraulic problem, he surely would have won. To keep up with the English driver, Vettel was risking a lot.

"Massa handled a good race," he continued. "Unfortunately, if a driver starts from a bottom row, he is likely to run into a car clash. After getting back on track in the last position and changing strategy, he was able to get up to the 8th position, making good passes. The Brazilian driver is probably getting back to his old self again."

As for his protege, Minardi urges Ferrari to get its act together as it cannot rely on luck forever. "It's positive especially if you get a third position after spending an uneasy weekend start," he said. "Maranello has to seek some tenth(s) to support Alonso, as the Italian team can't always rely on miracles.

"We still have four contenders to the world title and Ferrari is 29 points over Vettel, so, positioning could be enough, even if they have to improve performances and research."