Toronto ball kid surprises Ukrainian tennis star with adorable letter

There have been several wholesome stories from this year's National Bank Open in Toronto, but this one interaction between an eight-year-old ball kid and Ukrainian tennis star Marta Kostyuk takes the cake.

Ahead of Kostyuk's first-round match against Canada's Katherine Sebov, she was handed a handwritten note from the young Tennis Canada ball kid assigned to walk her onto the court at Sobeys Stadium.

Just as the cameras started flashing, the young fan pulled a piece of paper from his pocket and handed it to Kostyuk.

The note, which Kostyuk later shared on Instagram, read:

"Good luck today. My name is Marcus. I am 8 years old. Never give up. I will be cheering you on."

A photo of the letter that Marcus wrote was shared on Kostyuk's Instagram. (@martakostyuk)

The heartwarming message from Marcus appeared to be a good omen for the 24-year-old Ukrainian, who has won her first two matches at the National Bank Open and advanced to the Round of 16 for the second consecutive year.

Kostyuk arrived in Toronto playing some of the best tennis of her career. She won her first WTA 1000 title two months ago in Madrid and entered the National Bank Open as the No. 10 seed.

Though her next match on Saturday will be her toughest.

Marta Kostyuk, 24, has won her first two matches at Toronto's National Bank Open. (Dan Hamilton/Imagn Images)

Kostyuk will face six-time Grand Slam champion Iga Świątek of Poland on Saturday with a quarterfinal spot on the line.

There's no word whether her young fan, Marcus, will be in the Toronto crowd for that match. But even if he's not there in person, it's clear from his adorable note that he'll be cheering Kostyuk on from wherever he is.