Alain Prost believes McLaren must deliver this weekend in Germany if the team is to stand any chance of beating Red Bull and Ferrari.

McLaren led the way early on this season, but after a lacklustre performance at Silverstone slipped to fourth in the Constructors' championship, while Lewis Hamilton - the teams only realistic hope in the drivers' championship - also lost further ground and now lies 37 points off Fernando Alonso.

Speaking ahead of the tenth round in the 2012 F1 World Championship, Prost added that Alonso will be tough to beat now, although his money is still on the Red Bulls.

"It looks like McLaren has lost some ground for different reasons, and obviously it looks like they do not understand what is happening with the new tyres, which is not good news," Prost told R-Sport.

"I really thought that from the beginning of the year they would be the favourite because they started quite well, but they lost ground and it's very difficult to understand.

"If they don't come back immediately, from Hockenheim, the next race, I think it's going to be difficult. In front, Red Bull and Ferrari are very motivated and it's going to be tough.

"Red Bull, for sure they will be there until the end of the championship, and it will be very competitive.

"Alonso and Ferrari, it was a big surprise for me because I could not imagine that they could be that competitive and they came back quite well. Alonso is really pushing hard, he's number one in the team and he's going to be helped by [Felipe] Massa, you could say he's going to be difficult to beat.

"But I still think Red Bull at the end are going to win the championship again," Prost summed-up.