Federer, a 20-times Grand Slam champion, has won tournaments on every playing surface in his sport, and Mourinho spoke of his admiration for the Swiss player's adaptability.
A labouring Manchester United side can turn their attention to the Champions League on Wednesday night and it is fair to assume that one midfielder will be handed a start in the Group H match against Young Boys in Switzerland.
United have left Antonio Valencia back in Manchester as they didn't want to risk his troublesome knee on the artificial surface but Luke Shaw is back in contention after missing the Watford game due to concussion.
"I'm happy but you know I was happy after the Tottenham defeat, not with the result but with many things I saw and we felt that match was okay, was the beginning of our improvement".
Defender Luke Shaw will also return having overcome the head injury that he suffered on England duty, while there could be a midfield position for summer arrival, Fred, as Ander Herrera is still struggling to prove his fitness.
Asked for his views on the pitch, Mourinho said: "I don't want to use that, especially before the match, as a possible excuse for a not very good performance".
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"Valencia's situation, we need to protect his clinical situation, apart from that we go with everything we have and have to try and win".
"It is premature to be speaking about our chances when we didn't even play the first match", Mourinho told a news conference on Tuesday.
Man United lost away to FC Basel - the team normally representing Switzerland at this level - last season but have never played a competitive game against Young Boys.
Tonight's clash will be the first ever meeting between Young Boys and United in European competition.
Marcus Rashford is line to start, meanwhile, with the striker set to accompany Romelu Lukaku in attack.
"It's clear they are not used to pitches like this, so in the beginning I guess it will be a special feeling, but with training and the warm up I think they will be all right".