Mats Wilander says the attitude on court of Roger Federer during his defeat at Halle was 'alarming' going into Wimbledon.
Federer withdrew from the French Open after three matches to devote himself to his grass court preparations.
However, he played just two matches in Halle, his only Wimbledon warm-up, before losing to Felix Auger-Aliassime.
After that defeat he said he was disappointed with his own attitude, and Wilander is concerned for the 39-year-old.
Asked if Federer shown some vulnerability to his rivals with his poor attitude, Eurosport expert Wilander said; "I'm not sure if he's ever shown it or not.
"I actually saw him show it one time against Gustavo Kuerten at Roland-Garros, where he looked not interested to be there and was willing to hit the grass courts.
"So, I think that he's most probably felt like that before but for him to actually point the finger at himself - that's alarming.
"I think what happens when you do that, the thing we never talked about, it also puts a green light in the locker room to the rest of the field.
"Like: 'wow, even Roger Federer doesn't feel like fighting to the very end with a good attitude these days, so you know what Roger, you are 39, I am 21, I'm going to be out there for five hours if I have to. Even if you're Roger Federer'."
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