Jarrius Robertson's irresistible personality and positive attitude has inspired the team as he fights a chronic liver disease. In late April 2017, Jarrius' wait for a new liver ended, enabling a transplant. (6:46)

New Orleans Saints superfan Jarrius Robertson underwent surgery Sunday to receive a long-awaited liver transplant, his father, Jordy, tweeted.

Jordy Robertson said the surgery, which he earlier estimated would take eight to 10 hours, went "great," but the next few days following the surgery were important for his 15-year-old son.

Surgery went GREAT! JJ is resting now with NEW, working liver 🙏🏻 We will see him in a few hours. Next few days of monitoring are big - Jordy — Jarrius Robertson (@Jarrius) April 30, 2017

Jarrius, who signed a "contract" last year on "Good Morning America" to become an official "hype man" for the Saints, has become a larger-than-life figure around the team, handing out an award on the NFL Honors awards show with Sean Payton and Harry Connick Jr. earlier this year, among other appearances.

Saints owners Tom and Gayle Benson called Jarrius on Saturday, while Payton and quarterback Drew Brees wished him well on Twitter.

Pray for @Jarrius today as he receives his liver transplant in New Orleans. Can't wait to see you running around the #Saints facility, JJ! — Drew Brees (@drewbrees) April 30, 2017

Athletes from other sports, such as women's soccer player Carli Lloyd and Atlanta Hawks center Dwight Howard, also tweeted to support him.

Robertson battles biliary atresia -- a chronic liver disease that affects his physical growth. He has been in and out of hospitals since receiving a liver transplant when he was 1. At one point, he was in a coma for an entire year.