World number three Roger Federer has had a year of resurgence back to his absolute best, and he is now aiming for his 20th Grand Slam title at the US Open in New York.Although his initial struggles against the likes of Frances Tiafoe and Mikhail Youzhny brought concerns among the fans despite ending up on the winning side, Federer hit form from the third round as he outlasted Feliciano Lopez in straight sets to square up against Philipp Kohlschreiber at the Arthur Ashe Stadium.Ahead of the fourth round tie, the Swiss ace produced a really nice gesture as he warmed up for the match by hitting with cancer survivor Mark Kjajekian.The young boy, who is an avid admirer of Federer, admitted that the former world number one is his idol.Coming up against his hero, Kjajekian showcased his talent with the racquet and even pulled off an outrageous lob, leaving Federer stranded near the nets.Federer, later during the post-match interview, stated what a privilege it was to have the young lad on the court.The 36-year-old was quoted by Metro saying: “I mean, look, met Mark, a little boy.“He’s had a rough life so far, you know. But I think making a dream come true for other people is something that I’m in a privileged position to be in."He confessed the joy he felt meeting up with him and he was glad to be an inspiration to him throughout the difficult period.“I’m his big hero, apparently. He looked to me in the difficult times. It’s very nice to finally get to meet these people, or this little boy.“I’m happy I was helpful without knowing it, you know. Then for me also it’s a nice moment, you know, to meet someone like him. Even played some balls with him, which is even better.“I wanted to make sure he got the full treatment, the best experience possible.”You can watch a couple of clips from Federer's knock with the young boy in the videos below.

Federer won the match against his German rival with the scoreline 6-4, 6-2, 7-5 to set up a quarter-final date at the Flushing Meadows against Argentine star Juan Martin del Potro, who secured an impressive victory over Dominic Thiem in an epic five-set thriller.