Roger Federer gets huge boost as Stan Wawrinka makes honest admission ahead of Rotterdam
ROGER FEDERER may have to beat countryman Stan Wawrinka in the Rotterdam quarter-finals to go back to world No 1 - and he's got a huge boost ahead of their potential clash.
Stan Wawrinka will feature in the Rotterdam tournament this week
Wawrinka, 32, lost to Bosnian qualifier Mirza Basic at the Diema Xtra Sofia Open on Saturday as he continues his recovery from a knee injury.
And the Swiss admitted after the game that he knows is not at his best.
He said: "I was trying to be positive, trying to fight, knowing that I am not playing my best tennis but still had a chance to win, to make a final.
“I am sad with the result but there are a lot of positives to take from the week.
Stan Wawrinka could meet Roger Federer in the Rotterdam quarter-finals
“I knew that it would be difficult but I think that it was a positive to have three matches in a row, to win two matches.
“But it cost me more energy because I am not used to playing matches... in general, I am playing every day a little bit better, feeling something new but I still have a lot of work to do to be back to my top [level]."
Federer needs to reach the semis in Rotterdam to return to the top spot for the first time since 4 November 2012.
Wawrinka is the fifth seed at the ATP World Tour 500 event.
Roger Federer can become the oldest world No 1 this week
He added: “There are a lot of things I am doing well, playing well, moving well. But again, it is a part of the process to play my more matches, to get confidence.
“It was really positive to fight and win two matches.
"To be in the semi-finals today, I would have loved to win one more match... but I need to take the positives for the week.”
Wawrinka will play wildcard Tallon Griekspoor in the second round in Holland.