Juan Martin Del Potro's father Daniel passed away earlier this week and the player posted an emotional letter on social media.
The 63-year-old Daniel underwent a heart operation in December, but his health deteriorated and he died on Monday.
He leaves behind his wife Patricia, son Juan Martin and a daughter Julieta.
Former world No 3 and 2009 US Open winner Juan Martin took to Instagram to share an emotional tribute to his late father.
"You have left us here heartbroken, but we know that you are resting in peace like you deserve," he wrote.
"Now you have joined your other angel, and I ask that you please watch over my mom, my sister and me from above. You are our true and only champion.
"Thank you for raising me with values, with honesty, with sacrifice and for doing the impossible for me to be able to achieve my dream of being a tennis player.
"I don't know how I’ll live without your presence, but I'll definitely apply everything that you taught me to never give up. I love you pa!!"
- TEAMtalk media