TORONTO — Kevin Durant had just departed for the locker room and an uncertain future when DeMarcus Cousins entered the game for the Golden State Warriors for the first time. It was Monday night at Scotiabank Arena, and a cloud had settled over Game 5 of the NBA Finals.

Durant’s teammates could sense that he had sustained a serious injury, but Cousins and the rest of them played on, compartmentalizing their concern. Their business was basketball, and real life would need to wait. Given his own injury history, Cousins could have been more affected than most. But he somehow excelled in a game that the Warriors had to win.

“We play hard — simple as that,” Cousins said after scoring 14 points off the bench to help the Warriors escape with a do-or-die, 106-105 win against the Toronto Raptors.

But then, Cousins began to vent — about the people who had criticized Durant in recent days for not returning sooner, about the opposing fans in the arena who had cheered when Durant tumbled to the court in obvious distress, about the nature of a profession in which athletes are treated as commodities.

“It’s always about what we can do between those lines,” said Cousins, who returned to the court this season after sitting out for a year with a torn Achilles tendon. “That’s all that ever matters. Once we lash out and do human-type things, then we’re considered bad guys.”

Cousins was speaking with emotion, and perhaps for good reason: After witnessing the criticism that Durant has absorbed this season, Cousins also has a keen understanding of the hard road that Durant could face after leaving Monday’s game with a right Achilles injury.

Durant was scheduled to undergo an MRI on Tuesday to determine the extent of the damage. But it appeared to be severe.

Durant said on Instagram, “I’m hurting deep in the soul right now, I can’t lie. But seeing my brothers get this win was like taking a shot of tequila. I got new life, lol.”

“He went out there and sacrificed his body,” Warriors guard Stephen Curry said, “and we know how it turned out.”

The Warriors, who trail the Raptors three games to two in the best-of-seven series, with Game 6 set for Thursday night in Oakland, are sure to face questions in the coming days about their management of Durant, who had not played since May 8, when he strained his right calf in the Warriors’ second-round series against the Houston Rockets.

Coach Steve Kerr declined to elaborate on the decision-making process that had led to Durant’s return for Game 5. He instead deferred to Bob Myers, the team’s president of basketball operations, who simply said that it had been a “collaborative decision” without offering specifics.

“I don’t believe there’s anybody to blame,” Myers said, “but I understand this world, and if you have to, you can blame me.”

Not that anyone needed reminding, but Durant was exceptional in the 12 minutes that he was on the court. He made 3 of 5 shots, including all three of his 3-point attempts, and scored 11 points. He grabbed two rebounds. He jawed with the Raptors’ Fred VanVleet. It all looked and felt quite familiar. Durant was so good, in fact, that his performance seemed to feed into the false narrative that he had been too painstaking in his rehabilitation, that he had somehow been reluctant to make a return.

Afterward, Kerr said he was deeply conflicted: devastated for Durant, but proud of his team for playing with so much resilience.

“They have accomplished so much over the years, and that doesn’t just happen, and it doesn’t just happen with talent,” Kerr said. “There has to be more that goes into it, and it’s that fight, that competitive desire.” He added: “It was brilliant to watch.”

At the same time, it was one of the more morose victories in the history of the NBA Finals. Durant left the building on crutches. Myers broke down in tears. And Kerr spoke with the hoarse monotone of someone who sounded as if he had been gargling sand.

“An incredible win,” he said, “and a horrible loss.”