A couple of days ago Serena Williams was in the stands cheering old friend Grigor Dimitrov.
And Tuesday arrived one of the superstars of the sport this century.
Mr Roger Federer, five time US Open champion.
Federer was given the loudest cheer by fans at the Arthur Ashe stadium, which he duly acknowledged as he watched the night session.
On Federer being at her match against Qinwen Zheng, Aryna Sabalenka quipped, after her quarter-final win: 'I'm pretty sure he came to watch Tiafoe and Dimitrov. But still I was like I have to play my best tennis. I have to show my skills, my slice skills.'
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