CHICAGO – Given how most teams’ rotations tighten up in the playoffs, their benches growing shorter, the odds of six point guards playing significant or at least memorable roles in a single postseason game were long.

And yet there they were, a half dozen strong, either setting the tone, dictating the terms, determining the outcome or punctuating the evening overall in Boston’s 104-95 Game 4 victory over Chicago Sunday at United Center.

For the Bulls, whose 2-0 lead in the best-of-seven series is gone, there was the point guard who didn’t play, Rajon Rondo, and the three who did. Rondo’s fractured right thumb has him on the sideline, where he sits on the bench with much of Chicago’s pace, swagger and decision-making. He has been there since the injury was diagnosed before Game 3, his hand and wrist in a cast that looks far more supportive than the backups he left behind.

Those three – Jerian Grant, Michael Carter-Williams and Isaiah Canaan – were overmatched in Chicago’s two defeats at home. Even coach Fred Hoiberg’s promised quicker hook in Game 4 wasn’t swift enough. Grant started again and was yanked after just 4:41, by which time the Bulls trailed by 10 points. Carter-Williams subbed in and lasted about five minutes before he too was pulled, his team’s hole dug deeper to 13.

Compared to the first two – who have been given opportunities this season based on their reputations and dreaded “potential” only to shrivel in the moment – Canaan might as well have been planted behind glass etched, “Break only in case of emergency.” The slightly round 6-footer appeared in only 39 games overall and in just six of Chicago’s final 26.

Canaan’s contributions after Valentine’s Day: 1.2 points, 0.3 assists and 3.4 minutes per game on 2-of-9 shooting, total. Canaan’s wholly-unexpected contribution in Game 4: 13 points, three assists and two steals in 34 minutes, 4-of-10 shooting that included 3 of 7 on 3-pointers, and an exit score of plus-11 on a night his team lost by nine.

As much as folks might have scoffed when Canaan first was summoned, they wound up respecting the job he did as an emergency fill-in. The best of the non-Rondos for Chicago, Canaan looked almost noble in how he had stayed ready, stepped in and stemmed a reasonable amount of bleeding at the position.

It was, however, the game’s other Isaiah – Boston’s Isaiah Thomas, the game’s fifth point guard of note – who determined the outcome.

In the spotlight since the series’ eve for a horribly wrong reason – his 22-year-old sister Chyna was killed in a one-car accident south of Seattle on April 15 – Thomas had participated in the first three games while teammates and friends circled the emotional wagons. Outsiders wondered about his emotions and ability to focus, or not, on basketball at such a personally wrenching time.

Thomas, a natural NBA underdog in the best of times at 5-foot-9, had averaged 23 points and 5.7 assists before Sunday. But finally in Game 4, he both looked like his old self and provided the spark of victory.

Thomas scored 33 points, matching his Game 1 production, but this time he saved the Celtics when they needed it most. The Bulls’ best stretch of the night came at the start of the second half, as they defended more diligently and clawed all the way back from what had been a 20-point gap.

The Boston point guard, already lugging four personal fouls, came in with 5:12 to go in the quarter and the game tied at 63-63. On the Bulls’ next possession, Robin Lopez’s hook even got Chicago in front. Then it was Thomas’ turn.

He scored 10 of the Celtics’ next 12 points and assisted on Al Horford’s layup in the run to give Boston a 75-65 cushion. He solved the Bulls’ thicket of bodies and outstretched arms near the rim for layups or, if fouled, sank free throws. When the Bulls edged closer in the fourth quarter, Thomas went at them again, getting five consecutive points to make it 86-76 with 9:01 left. The gap never dipped below eight after that.

Thomas grabbed the game and made it his own … so much so that Hoiberg angrily pointed out an unfair advantage that the undersized guard might or might not have.

“Let me say this: Isaiah Thomas is a helluva player,” the Bulls coach said, revving up. “An unbelievable competitor. He’s a warrior, everything he’s going through right now. He had a helluva game tonight.

“But when you’re allowed to discontinue your dribble on every possession, he is impossible to guard. He’s impossible to guard. When you’re able to put your hand underneath the ball and take two or three steps and put it back down, it’s impossible to guard him in those situations.”

For Hoiberg, who works hard to stay civil and well-mannered in the most trying circumstances, this was the equivalent of a meltdown. Aware that he’d no doubt be hearing from the NBA and surely writing a sizable check, he fielded a few more questions about his Thomas objections with quick, direct answers.

Was it worse than usual Sunday? “No.”

Had he pointed it out to the refs previously in the series? “Yes.”

Had they indicated they would watch for the discontinued-dribble violation? “Yes.”

When asked if that call ever gets made in today’s NBA, Hoiberg amplified: “That’s a great question. They talk about it every year, being a point of emphasis. It should be called.”

After stating he was done talking about the matter, Hoiberg exited stage left feeling as burned by Thomas as Canaan, Jimmy Butler and all the other Bulls who tried to guard him. But Thomas stepped up to the podium next and gave a dismissive if not persuasive rebuttal.

Told of Hoiberg’s remarks, Thomas – with his two sons next to him at the podium – smiled. “I mean, that’s not the reason why I’m ‘an impossible cover,’” he said. “I guess he’s going to just keep saying it. I’ve been dribbling that way my whole life. I don’t know what to say to that.”

How often do the referees whistle him for carries? “I don’t think I’ve been called for it one time this year,” Thomas said. “So I don’t think it will change. I could see if I’ve been called for it a couple times a game.”

If Hoiberg’s ire and expected fine buy the Bulls two or three pricey Thomas turnovers in Game 5 Wednesday (8 p.m. ET, TNT), it probably won’t matter much if they’re stuck using their three healthy point guards and going without their fourth. The Celtics, of course, are happy to have theirs back – as much as Thomas reasonably can be right now.

“Mentally and emotionally, I’m not here,” Thomas said, later praising the Boston organization and “the whole world, really” for the support he has felt. “I just feed off what the guys give me. They give me a lot of confidence. I can’t do it without those guys. They believe in me. Being here is what makes me sane mentally and feel somewhat normal through these tough times.”

Oh, oh, oh. That sixth point guard referred to at the top of this tale? That was Derrick Rose. Making an odd cameo and sitting courtside in a corner of the court about 50 feet from the Bulls’ bench, Rose – traded last June to New York, rehabbing from yet another knee surgery, headed into free agency facing real on- and off-court questions – showed up at United Center to sample playoff atmosphere he hasn’t earned since 2015.

It was a point guard-apalooza Sunday, feature two who looked lost, two who were hurt, one who at least tried hard and one who, uh, carried off the victory.

Steve Aschburner has written about the NBA since 1980. You can e-mail him here and follow him on Twitter.

The views on this page do not necessarily reflect the views of the NBA, its clubs or Turner Broadcasting.