five-set match of his life. It's quite amazing at this age to only be pushed there, or for himself to be in that situation."
"But, yeah, he's a dangerous player. (He's) very athletic obviously, (he's a) good athlete."
"So regardless of who I play in the semis it's gonna be tough."
Tsonga meanwhile was quick to suggest that he will go in as the underdog because of Federer's considerable experience but he won't be overcome by the occasion.
"What do I have to do (to win)? I have to play my best tennis," Tsonga said.
"Roger played unbelievable today again, because Nikolay was in good shape, so it's gonna be tough."
"But like today, I will give everything and we will see."
"It's good to have experience ... Roger have experience because he's won like 15 or 16 Grand Slams."
"But he won the first one without experience, so I think at this level you never know what's (going to) happen."
"Yeah, I think, I don't know (if he'll handle the occasion). I feel good."
"I won two tough matches, my two last matches were tough, and I did it. Why not against Roger?"