"I grew up watching him play," Dial said. "He's always been there my whole life, like a big brother, helping me with everything. I always wanted to go [to Mansion] because of him. He's like a role model."
Dial eventually finished with 16 points, but when he struggled early, Johnson settled his nerves.
"It helped me a lot," Dial said. "Coming into this game, I just knew we needed this win and I'd do anything necessary to get it, but I was frustrated because I was missing shots I usually make. And my coach just told me to calm down and let the game come to me. In the second half, I just played my game and we started winning."
Dial also added 10 rebounds, five steals and three assists. He was helped by 16 points and eight boards from senior forward Derrick Gant.
Senior guard Shawn Ruffin led Mastery North (12-9, 6-6) with 16 points.
The victory means a meeting with Division B Sankofa on Tuesday in a preliminary playoff game.
"During the whole season we had a lot of ups and downs with players being eligible to play and losing to teams we thought we should beat," Dial said. "And we're just looking forward to going out with a bang."
After graduation, Dial isn't sure what's next, but he reports some D-III hoops interest. He lives with his mother, Aiesha Somerville, in North Philly, in the same neighborhood where Johnson grew up.
And Dial plans to keep following Johnson's lead.
"He's my role model. He's been my role model my whole life. I wanted to be like him. He went to Strawberry Mansion and played in college. He was a good student and graduated from Gwynedd Mercy. He's just a good role model."
On Twitter: @AceCarterDN