Harden, who was guarding center Steven Adams near the block, sprinted to close out on the stunningly sizzling Dort, jumped and extended his left arm as high as he could. Harden blocked Dort's potential go-ahead 3-pointer with 4.8 seconds remaining, a series-saving defensive stop by an NBA scoring champion who had endured yet another off night in an elimination game.
During the dead ball after the block, Harden released a primal roar, letting out a long night's worth of frustration.
"Like [Nipsey] Hussle said, never let a hard time humble us," Harden, referring to the late rapper, said after the Rockets advanced to the Western Conference semifinals with a 104-102 win in Wednesday's Game 7 in Lake Buena Vista, Florida. "It was just one of those nights offensively, so I just wanted to change the game defensively. I think I did that."
The Rockets next face the top-seeded Los Angeles Lakers, with Game 1 on Friday (9 p.m. ET, ESPN).
Wednesday's game could have gone down as another season-ending dud by Harden, a perennial MVP candidate who has had some of his worst outings in Rockets elimination games, twice going 2-of-11 from the field in Houston's final playoff game, committing 12 turnovers in a Game 5 loss to the Golden State Warriors in the 2015 West finals and fouling out of a Game 6 loss to the San Antonio Spurs in the 2017 second round.
Harden, the NBA scoring champion the past three seasons, had another rough offensive outing in Game 7 against the Thunder. He scored 17 points, less than half his season average, on 4-of-15 shooting.
"Offensively, I played like s---. Excuse my language," Harden told ESPN's Cassidy Hubbarth in an on-court interview immediately after the game. "I couldn't hit a shot. I turned the ball over. Just doing everything that's not supposed to happen, but I just kept sticking with it. My teammates gave me confidence throughout the course of the game, and defensively I had to make a play."
Harden made that play by denying Dort, the undrafted lockdown defender who had a shocking shooting night in Game 7, breaking Harden's Thunder rookie playoff scoring record with 30 points. Dort, a 29.7% 3-point shooter this season, was 6-of-12 from long range on Wednesday.
There's some irony in Harden, often harshly criticized for being an uninterested defender, saving the Rockets' season by coming up with a clutch stop. However, as many in the Rockets organization have been shouting from the rooftops, Harden's reputation for being a dreadful defender is outdated.
"James has been playing defense," said Rockets co-star Russell Westbrook, who had 20 points in Game 7 to help eliminate his former team. "I think if media and people actually look at the numbers -- since you guys like to look at numbers -- look at them and then you'll get your answers. James defends."
Harden led the NBA in steals with 125 this season. He also ranked sixth in the league in deflections with 220, an indication of how engaged Harden has been on that end of the floor. Harden has consistently rated as an elite post defender in recent years -- giving up only 0.68 points per post-up possession defended this season, per NBA.com/stats -- a major reason why the Rockets felt they could survive defensively playing a historically small lineup.
"You know how the narratives go," Houston coach Mike D'Antoni said. "Once you get stuck with a label, it's tough for NBA players to shed that label. I've coached so many guys who have improved different areas of their game where people just keep writing about how bad it is, because they don't really study the film and watch and understand totally. And I think James' defense got a lot better.
"He's been locked in, and I think he knows that for us to be able to win at a good clip, the defense has to be there. He's just taking the challenge and doing a great job."
Harden, who averaged 29.7 points and 8.0 assists in the series despite stellar defense by Dort, has repeatedly emphasized that the Rockets' defense would determine whether they would have a legitimate chance to win a championship.
Houston held Oklahoma City to only 101.7 points per 100 possessions in the series, giving the Rockets the best defensive rating in the bubble playoffs so far.
Harden said he felt an extraordinary sense of satisfaction that his most impactful and memorable play of the series -- "one of the top" plays of his career, he said -- came on the defensive end of the floor in crunch time.
"It's cool to get 40 or 50 points or shoot the ball extremely well," Harden said. "Obviously, we all want to do that. But for it to pay off when it counts on the defensive end, it shows that I've been engaged and locked in. For it to show in a clutch moment, it means a lot."