Onlookers made desperate attempts to revive the boy using a defibrillator, as his teammates, their parents and dozens of spectators watched on in shock.
Among those to witness the tragic incident, was Tyreez’s basketball coach Matt Burd.
“Coming back to the bench after the first siren had gone for half-time I just thought he had kind of tripped over,” Burd told The West Australian.
“I went over to him and said ‘are you all right’, but he just never got up. I went to get help, I’m not a doctor or anything but there were nurses all around. He had help but they just couldn’t save him.”
In statement to the media, the Mundriona family remembered their beloved Tyreez as a keen athlete.
“The family would like to clarify that Tyreez had no pre-existing medical conditions," the statement read, according to The West Australian.
"They want to thank all families and staff of Lakeside Basketball for their immense love and support and a special thank you to Wesley College in South Perth for making him the awesome boy he was, and teaching him the core values that took him through his short-lived life.”
Tributes have been flowing for the Year Four student on social media while others have laid flowers and basketballs outside the leisure centre where the tragedy occurred.
Burd joined the tributes, describing Tyreez as "down to earth" and a "lovely, gentle, caring kid" who cared deeply about his teammates, according to The West Australian.
"We’re all wearing black tape today and it’s not just Lakeside. It’s most people in the WA basketball community.
"Everyone is different and obviously the people who are closer get hurt more but everyone feels a similar feeling. The main thing is everyone is caring and just checking other people are okay.
“His sudden and tragic death has reminded everyone in the club how life is so fragile and can be taken away in an instant.”
A coronial investigation is currently underway.