If you wanna be the best you have to be able to beat anyone, otherwise you don't deserve to win. Anyone could all catch fire and beat him. He has an excellent record against the players in his quarter, except Raonic, who he lost one clay match to. At this point it's not even certain Raonic will reach R4. I really don't get all this worrying. You either believe in him or you don't. If he's not in form he doesn't stand a chance anyway. We should be happy that he didn't draw Berdych or Del Potro in the QFs. I prefer Tsonga by a mile.
He's shown that on his game, he can handle and frustrate Tsonga. He can do this to Berdych and Delpo too but I think they have more potential just to hit him off court than Tsonga, who is a bit more creative on court.