How Lonnie Walker IV impressed Joe Mazzulla at the first real Celtics audition

Despite making his Celtics debut more than a week earlier, Saturday night was Lonnie Walker IV’s first real opportunity to prove himself to Boston’s decision-makers.

The veteran winger played a team-best 25 minutes in the Celtics’ 139-89 rout of the Philadelphia 76ers at TD Garden, doubling his total from the first two preseason games combined (11).

Walker scored 11 points on 4-for-7 shooting (1-for-4 from 3-point range). He also dished out seven assists, grabbed four rebounds, blocked a shot and added two steals while playing against a rotating cast of Sixers benchwarmers.

The competition was far from fierce – Philly left all of its starters and most of its veteran reserves in the loss – but Celtics coach Joe Mazzulla liked what he saw from Walker, who signed an Appendix 10 tryout contract with Boston after he couldn’t land a guaranteed deal in free agency.

“I think he was really good,” Mazzulla said. “I think it’s a change coming here because it’s just a different style of basketball and I like his openness to learning. I like his patience. It’s funny when you have a guy like him who’s been in the league for seven years.

“I saw some things from him today that maybe he doesn’t think are important, or other people wouldn’t, but they’re really, really important things, defensively and then offensively. Whether it was his positioning or whether it was a little cut he made or an interpretation he made, those things add a lot because they open up possibilities.”

For Walker, who didn’t see the court until the fourth quarter of the Celtics’ two exhibition games in Abu Dhabi, this was his first chance to test his chemistry with some of Boston’s regulars. He was part of Boston’s second unit with players like Payton Pritchard and Sam Hauser and later appeared alongside players further down the depth chart.

“This is really my first time getting my first taste of playing on the team — and getting reps in general,” Walker said. “…This is my first time playing with Payton and all the other guys and stuff. So I just spontaneously try to find out where my comfort zone is.

“But overall I give myself credit – it was fine. I think there is room for improvement and the only way I can improve is to constantly watch film and see what I can get better at.”

Based on his experience (322 career appearances, 88 starts, significant playoff minutes not until 2023), Walker is likely overqualified for his E-10 deal, which includes no guaranteed money and could ultimately result in a trip to the G League. But the 25-year-old reported to training camp humble and hungry and said he would accept whatever role was given to him.

“I’m one of the first ones in the gym and one of the last ones out and coming in at night to take shots,” said Walker, who was one of the last players off the court after every Celtics practice. “I am doing everything in my power to make sure I am mentally and physically prepared for whatever might happen.

“If it goes as it should, I’m happy. If things don’t go the way they should, at the end of the day I can take my hat off to a man and understand that I did everything in my power to achieve what I could.”

Walker has two games left to prove to Mazzulla and basketball president Brad Stevens that he deserves the final open spot on Boston’s 15-man roster. The Celtics conclude their preseason with a home game against the Raptors – on Sunday evening at TD Garden and on Tuesday in Toronto.

“He just enjoys working hard,” Mazzulla said.