Stewart Donald has told Bali Mumba that the 'hard work begins now' after the Sunderland youngster penned a first professional contract.
The 17-year-old broke into the Black Cats' first team last season and has continued his rapid rise through the ranks in the current campaign, featuring three times for Jack Ross' side during the opening months.
The teenager has now seen his progress rewarded with a first professional contract which will see him remain at the Stadium of Light until at least 2021.
And, having been with the club since the age of 8, the deal is something of a dream come true for Mumba - who was delighted to share the moment with his supportive family.
Speaking about the deal, the midfielder told safc.com: “I am delighted to sign this because it has been a long wait.
“It is what I have been dreaming about since I was a kid. All the hard work is beginning to pay off and my family and I are all buzzing about it.
“It is a proud day for us all – I am just delighted to be able to stay at this club.
“My family have done so much for me over the years. They have helped me get here on a daily basis and for them I am truly grateful.
“To share it with them is amazing because they deserve this bit. They have done so much to help me get to where I am now and I am just so thankful to have them by my side."
Manager Ross was also delighted to see Mumba stay as the club look to retain their brightest youngsters.
“We are delighted to be able to retain our best young players and our most promising players," he added.
"I think for the club as a whole it is a really good reflection on the academy.
“They have brought him through and now he wants to stay. He is undoubtedly someone who will attract attention throughout the country because of his ability but hopefully it is a real statement of our intent about how we want to move the club forward.”
Meanwhile, owner Donald was one of many to send their well wishes to Mumba after he penned the deal - and revealed that he is excited to see how far the youngster can progress.
The Sunderland chief tweeted: "Congratulations!!! The hard work begins now. Well done Bali - I am sure the fans like me cannot wait to watch your development over the coming years"