The two were not originally scheduled to face each other, but were paired after their opponents pulled out. That left a 10-round, non-title contest that was no more than a tune-up for Laval, Que.'s Pascal, who was already booked for a bigger fight in March against world champion Sergey Kovalev.
It ended in confusion, as Pascal hit Bolonti with a short right as they were coming out of a clinch along the ropes in the second round and the Argentine dropped to the canvas. He stayed there for several minutes, taking oxygen from ring medical staff before he was taken out on a stretcher to hospital.
Referee Michael Griffin ruled it a no contest due to an unintentional foul at 2:29 of the second, so the records of Pascal (29-2-1) and Bolonti (35-3) remain unchanged.
And it should not stop Pascal's showdown with Kovalev on March 14, to be held in either Montreal or Quebec City.
"It's an unfortunate incident," said Pascal, the former WBC champion. "It's too bad because I wanted to put on a good show.
"I was doing well the first two rounds. It happened really fast, but he hit me once behind the head and again on the ear and I didn't hear the ref say break. I saw an opening and I hit him. If he's really hurt, I wish him a full recovery."
The crowd booed, but it was difficult to determine if there wasn't some play-acting on both sides.
Bolonti looked to have a slight advantage in an uneventful first round, but Pascal dropped the Argentine with a left jab early in the second and went on the attack.
Then the two clinched in the middle of the ring. Bolonti swung twice at Pascal as they moved together to the ropes. They were just coming out of the clinch when Pascal hit him on the side of the head.
A first, it appeared Pascal would lose by disqualification, which may have compromised the Kovalev bout. So having it ruled a no contest came as a relief.
There was no comment from the Bolonti camp, but Pascal's corner was convinced he stayed down in a bid to win by DQ. Trainer Roy Jones Jr. said Bolonti's reaction was worthy of Hollywood.
"When you hit him for real and he really goes down, there's a difference," said Jones, the former middleweight king. "When Jean hit him with the jab, he got up right away because he was embarrassed that he got knocked down from a jab.
"When he started faking, there was no chance he was coming back. This punch wasn't as hard as the jab, but there was no chance he was getting up. It's disgusting."
Pascal is not known for illegal punches, but had no clear explanation for why he decided at that time to throw an illegal shot.
"He punched me on the ear so I punched back," said Pascal. "I didn't know the ref said break. That was an unintentional punch. I don't know what to say. I'm not a dirty fighter. I've never done that in my life."
Jean Bedard, president of Promoter InterBox, was relieved that Pascal didn't lose and came out of the bout without an injury.
Michel Hamelin, head of Quebec's boxing commission, said it was ruled a no contest because both fighters threw punches during the clinch.
"It was the referee's decision, not the commission's. The referee acted properly," he said.
Bolonti was conscious when he was taken from the ring.
"He seemed to be recovering but we didn't want to take any chances so he went to hospital," Hamelin said.
Pascal won the WBC title with a win over Adrian Diaconu in 2009 and defended it four times before losing a 12-round decision to Bernard Hopkins in 2011. Hopkins lost the WBC belt soon after, but had the IBF and WBA belts when he lost to Kovalev last month in Atlantic City.
The WBC title is now held by another Montreal fighter, Adonis Stevenson, who will defend it Dec. 19 in Quebec City against Russian Dmitry Sukhotsky.
Bolonti was originally set to fight former IBF super-middleweight champion Lucian Bute, but the Romanian-Canadian pulled out two weeks ago with a back injury suffered in sparring.
Pascal was supposed to face Don (Da Bomb) George, but the American was dropped when promoter InterBox arranged for Pascal to fight Bolonti.
The Pascal-Bolonti fiasco ended up as the second controversial card in recent years in Montreal, after a 2008 fight in which Bute's title was said to have been saved when he received a long count from the referee at the end of a clash with Librado Andrade.
In the co-feature, light heavyweight Schiller Hyppolite (14-1) knocked down 19-year-old Hungarian Norbert Nemesapati (15-1) in the third round and stopped him at 1:26 of the 11th to win an ill-defined title called the WBC International Silver belt.
The 28-year-old Hyppolite dominated from the start, but it took a stiff uppercut followed by a flurry of punches in the 11th to end the scheduled 12-round bout.
There were no surprises on the undercard.
Pascal started his own promotion company and one of his first deals was to co-promote American super-featherweight Joel Diaz (18-0), who floored Mexican journeyman Pedro Navarrete (28-20-3) with a body shot at the end of the fourth round.
Welterweight Junior Ulysse (5-0) was in his first eight-round bout. He won all eight for a unanimous decision, but couldn't knock down Lukasz Janik (12-8-1) of Poland.
Same for light welterweight David Theroux (5-0) of Sorel, Que., who won all six rounds but couldn't put away another Pole, Maurycy Gojko (22-45-3).
Light middleweight Steven Butler of Montreal handed French left-hander Lyes Chiabi his first career stoppage with a TKO 1:12 into the fifth round of a free-swinging eight-rounder.
Heavyweight Bogdan Dinu (12-0), a Romanian fighting out of Montreal, had Frenchman Mickael Vieira (14-5) on the canvas twice en route to a knockout at 2:49 of the first round of their eight-rounder.