The 19-time Grand Slam champion was on his way to court, when he undertook a brief interview with Sky Sports previewing the clash with the young German.
While he declared his own recovery had gone to plan after his opening win against Jack Sock, the Swiss sent his best wishes to the world No. 1.
Nadal withdrew from the season finale due to a knee injury that has plagued him throughout the final few weeks of the year, with questions arising over how long he’ll be away from the game.
But Federer hope he’s back on tour sooner rather than later and admitted he’s missing having his long-time rival around at the O2.
‘It’s been easy [my recovery], had a day off yesterday,’ he said.
‘I played during the day time on Sunday so plenty of time there as well. I feel really good going into tonight.
‘Of course, it is a pity not seeing Rafa around anymore.
‘We all hope he recovers quickly and well from that and comes back strong next year.’
With Nadal out, Federer is the overwhelming favourite to lift the ATP Finals title for a seventh time.