Bruce Brown Jr., sidelined by a left hand injury, came onto the court during a timeout to join the celebration after Walker sank four 3-pointers in a 4-minute span Tuesday night, helping No. 10 Miami pull away from Boston University, 69-54.
"Since Bruce is down, I had to understand that I had to up my game," Walker said.
Making his first career start, Walker scored a season-high 26 points. He shot 9 for 15, went 5 for 7 from 3-point range and added seven rebounds in 28 minutes, also a season high.
He smiled when asked about his chest bump with Brown.
"It was definitely an ecstatic feeling," Walker said. "I was waiting for him. I saw him coming. I saw him excited. He was telling me, 'Stay aggressive, shoot the ball, attack the rim.' I had to listen to my older brother."
Brown is expected to miss one more game before returning.
Dejan Vasiljevic had 15 points for Miami (8-0), which remained unbeaten in non-conference home games since November 2015.
Boston U (3-4) still hasn't beaten a ranked team since 1959, and coach Joe Jones was impressed by the Hurricanes.
"They are a terrific defensive team," Jones said. "Offensively they're still growing, because these guys are young. They're just going to get better and better. They can be a factor in March."
Boston U never led but was tied at 30 at halftime thanks to a tip-in by Max Mahoney at the buzzer. Walker scored 16 points during a 25-8 run to start the second half that helped the Hurricanes take charge.
"It was a bit of a groove," Walker said. "Confidence exploded up to like 100 percent. The rim got huge. The ball got smaller. Everything was kind of going my way tonight."
Walker is coach Jim Larranaga's most highly touted recruit at Miami. His point total was the highest by a Miami player this season.
"He was certainly in the attack mode from the very beginning," Larranaga said. "Honestly, he just looked like Lonnie Walker to me. I mean, he scored 26 points and played great, but I've seen him play great a lot. This is just the beginning."
The Hurricanes shot 52 percent and went 11 for 21 from 3-point range. They rank fourth in nation in scoring defense and held an opponent under 60 points for the sixth time.
Mahoney had 12 points off the bench for Boston U.
Larranaga said Brown has been dealing with a sore hand for weeks and aggravated the injury recently. It will take two to four weeks to fully heal, Larranaga said.
Miami came into the game shooting 58 percent at the free-throw line and went 8 for 15.
Terriers guard Cedric Hankerson, a Miami native, went 4 for 17 and scored 10 points.
The Hurricanes have yet to trail in the second half this season.
Jones fell to 0-5 against ranked teams with the Terriers.
The Hurricanes play at George Washington on Dec. 16. Their next home game isn't until Jan. 7.
"We've got to treat every single game like they're No. 1 in the country," Walker said.
Boston U plays at Bethune-Cookman on Friday.
For more AP college basketball coverage: http://collegebasketball.ap.org and http://twitter.com/AP_Top25
Copyright 2017 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.