Jo-Wilfried Tsonga

Frenchman Jo-Wilfried Tsonga knocked out top seed Marin Cilic to reach the semi-finals of the Rotterdam Open on Friday afternoon.

The 2011 runner-up will take on Czech Tomas Berdych for a place in Sunday's final after upsetting Cilic 7-6 (10-8) 7-6 (7-5) in just over two hours.

Tsonga converted on his fourth set point in the opening set tie-break with a trademark forehand winner down the line before the big-hitting Frenchman took his opportunity in the second set tie-break to record his first win over Cilic since August 2011.

During his second-round match, Jo-Wilfried Tsonga noticed a ball girl was fighting back tears after being struck by a ball.

The Frenchman stopped play to check on the girl before looping his arm through hers and escorting her off the court.

Twelve months on, Tsonga has revealed the girl, Guiliana, sent him a heartfelt message of thanks.

"Dear Mr Jo-Wilfried Tsonga," the letter reads.