Joe Mazzulla recalled a quick story after Thursday’s practice. His father, Dan, played five seasons professionally in Chile and there was an instance of a game being decided by an aggregate best-of-two score differential. His dad’s team needed to win by six in the second game, but there was one problem: They led by just two with seconds remaining.

So, Mazzulla said, his dad’s team scored on its own basket to force overtime so it could have a chance to win by six.

Those circumstances were certainly unique. Mazzulla brought it up because his own unique situation earlier this week reminded him of it. The Celtics needed to win by 23 over the Bulls on Tuesday night to advance to the NBA’s inaugural In-Season Tournament’s quarterfinals, and successfully did so under non-traditional methods, which included intentionally fouling poor free throw shooter Andre Drummond while up 30 in the fourth quarter and keeping their starters playing in a blowout until there were less than two minutes remaining to ensure that they won by enough to advance in the tournament.

The strange scene and situation provoked questions about integrity and sportsmanship – even by Celtics players – but Mazzulla is hoping it will provide a valuable lesson for his team about playing hard no matter the circumstances, and building big leads into larger ones instead of letting their foot off the gas. Mazzulla referenced a conversation he had with Kristaps Porzingis, whose professional career began in Europe where playing for point differential is common.

“He can’t fathom why you wouldn’t play up 30 points to get it there,” Mazzulla said. “Like, that’s his definition of respect for the game, whereas the American definition of respect for the game is we all stop playing when it’s a 20-point game and let someone else go play for us. So it’s just a different level of expectations. So the in-season tournament has really helped give the perspective of, should we not be trying as hard as we could when you’re up 32 points or up 25 or up 18?

“So it’s just that level of perspective. So if we can at some point be the team that’s the best at playing regardless of what the score is, it allows us to build a mindset and habits.”

The Celtics have had some major issues over recent seasons blowing big leads. Last season’s embarrassing loss to the Nets when they blew a 28-point lead was the most jarring of Mazzulla’s tenure and he said that game taught him lessons about momentum within games. There are certainly more examples beyond that game.

Mazzulla acknowledges the Celtics won’t play perfectly all the time. Mental slippage and blown leads will happen. But in those moments, he wants his team to recognize what’s happening and figure out ways to regain focus. He thinks the situation that unfolded in Tuesday’s in-season tournament game can help them gain a new perspective that will benefit them in similar situations moving forward.

“The point differential has opened up the perspective of why teams blow leads, and why the difference in basketball here in America is different in Europe, because the expectation of point differential makes teams have to keep playing,” Mazzulla said. “Like the things that you’re seeing in the in-season tournament this year go on in Europe on a daily basis because of the structure that they play with. … You talk to players here who have only played in America, it’s a different perspective on, like, respect for the game. European respect for the game is like, do what we did against Chicago every single time because there’s always a point differential where, here, at some point, the other team concedes and you put in different lineups, and you just kind of hope the game’s over.

“And so regardless of if it’s 30 points and a point differential, or we’re up 18 with six minutes to go, can we play as hard as we can and not just hope for us, like be hopeful that we’ll win this game or get through it. Can we strive in those situations?” …

“At the end of the day, the core of that is, you have a lead, are you going to play to increase it or are you going to not play and allow it to decrease? So whether it’s an in-season tournament and there’s points differential or not, we have to get great at that space of, we’re winning and we got to work on keep winning, not relax.”

Injury report

Porzingis will miss his third consecutive game on Friday against the 76ers due to his left calf strain. Mazzulla said earlier this week that Porzingis would be re-evaluated after a week, and Friday will mark one week since he suffered the injury, so it’s possible he could return for Monday night’s in-season tournament quarterfinal game against the Pacers.

Porzingis was seen briefly after Thursday’s practice at the Auerbach Center, where he was wearing a sleeve over his injured calf and exercising on a stationary bike.