CLEVELAND, Ohio -- As soon as the buzzer sounded, ending the best game of Kevin Porter Jr.’s career thus far, the breathtaking rookie who continues to make strides each night had mixed emotions.

Porter scored a career-high 24 points on 9-of-15 from the field and 6-of-9 from 3-point range. It’s the most triples he’s hit in a game, the most points scored by a Cavs rookie since Collin Sexton on March 28, 2019 in San Antonio. In a late-game, confidence-building duel with MVP James Harden, one of Porter’s idols, the Cavs teenager had 16 points in the fourth quarter, trying to will his team to a much-needed victory. It was just the second time he earned high-stress crunch-time minutes -- a meaningful milestone in his development.

But the youngster also made two costly mistakes in the final 36.8 seconds that left him dejected.

“Of course I was upset,” Porter told cleveland.com. “I turned the ball over twice late in the game. Can’t do that. We lost.”

While others were greeting members of the Houston Rockets on the court, Porter lingered underneath the hoop. He was clearly somber -- a different demeanor than anyone would expect following a special night that left many beaming about his potential.

Jordan Clarkson came over to congratulate his bench buddy. Shortly after, Houston’s James Harden came over to dap up Porter, offering words of encouragement. Before Porter made his way through the tunnel that leads to the locker room inside Rocket Mortgage FieldHouse, Larry Nance Jr. -- one of Cleveland’s evolving leaders who often plays video games with Porter -- looked at him eye-to-eye, wrapped his arm around him and delivered his own message.

“I told him he’s going to be a monster,” Nance said to cleveland.com. “I will take winners all the time. He’s upset because he turned the ball over and that’s OK. Let things sting like that so you learn from them. At the same time, I told him, ‘Let it hurt for tonight, let it hurt while we are in the locker room or whatever it is and then forget about it and move on.’ Without him, we’re not even anywhere close to winning that game.”

PJ Tucker’s late 3-pointer gave Houston a four-point lead with under 40 seconds remaining. But the Cavs felt they still had a chance -- enough time (exactly 36.8 seconds) to mount another rally. All they had to do was execute quickly out of a timeout and get a stop at the other end. Head coach John Beilein drew up a play in the huddle, pegging Porter as the inbounder. As Collin Sexton came around a screen, Porter threw an errant pass that was stolen away by Westbrook. In transition, Westbrook found Clint Capela for a two-handed dunk and six-point advantage.

Still a two-possession game with 31.1 seconds, the Cavs called their final timeout and drew up a slightly different play. Undeterred -- believing in his passing ability -- Beilein picked Porter to trigger from the sideline once again. This time, Porter’s pass for Clarkson was deflected away by Capela and into Harden’s hands. Another costly miscue. Another late-game stumble. Two vital lessons.

“What I tell him is, ‘You haven’t been in those situations probably ever in your career. So the fact that coach trusts you out there is a compliment.’ The game is not won or lost on his turnover,” Tristan Thompson said. “It’s just learning curve. At the end of the day it’s about our young guys getting better every day. KP’s taking steps in the right direction.”

To focus on the two awful turnovers in a 29-minute individual gem would be misplaced. So much of this season is about Porter -- and other youngsters -- gaining valuable experience in moments like Wednesday night. Against high-level teams and players. By any measure, this was a massive leap forward for the kid.

“It doesn’t sour it for us. It shouldn’t for him either,” Nance told cleveland.com. “Coaches sure as hell don’t care about it because he’s 19. Think about that. He’s 19.”

Sometimes it’s easy to lose sight of that, especially while the team finger-points, eye-rolls and mopes its way through an energy-zapping losing skid that has now reached eight games.

But Nance is right. This is the 30th pick of the draft, the class wild card, and just 24 games into his career he’s already become a vital piece of Cleveland’s second unit. With more showings like Wednesday, he may become a staple of the team’s closing quintet. He’s averaging 12.8 points on 53.2% shooting and 52.4% from 3-point range over the last five games. Dripping with natural talent, Porter looks to be the brightest light in a gloomy season.

“I think he’s been, like a coach would say, trending in the right direction,” Thompson said. “KP’s starting to figure out his ability and figure out what he can bring night in and night out, especially against second-unit guys. What I’ve been telling him is he’s got a very special, unique chance to be very good in our league. I think he can be a great two-way guy. I think with his God-given ability and makeup, body structure, I think he has the potential to be a guy who can guard, but also score on the other end. I think he’s realizing just to make it simple because guys just don’t want to guard and he’s figuring that out. ... The kid has got something special.”

Porter showed all of those gifts Wednesday night. He poured in buckets inside and outside. He didn’t hesitate on some of his 3-point looks. He dazzled the crowd a few times with highlight-reel isos. He drained clutch jumpers, responding to Harden’s daggers. He repeatedly took the defensive challenge against Harden, the league’s leading scorer and one of Porter’s summer workout partners.

“I had fun guarding him for sure. It made me better,” Porter said. “Hopefully I made him better as a player. On to the next.”

Porter even pulled out a step-back jumper that looked awfully similar to his mentor’s lethal go-to maneuver.

“I’ve been saying it since he was at USA Under-17, he’s got a lot of James in him,” Thompson said of Porter. “That’s great for him. That’s great that a league MVP and guy like James Harden is able to allow a young guy like KP to come work out with him and learn from him. That shows a lot about James’ character, how he wants the game to continue to grow and wants to help the guys after him. So kudos to him for that. And for KP, take it advantage of that opportunity, soak it up like a sponge. That can help his game so much. They’re both lefties. As long as KP keeps working on that trey ball, he’s going to be problem in this league.”

As the Cavs were staring at another potential blowout loss, with the Rockets pushing their lead to a game-high 14 points in the second half, Beilein called for two subs, swapping in Clarkson and Porter.

That’s when the Cavs’ fortunes started to change. Porter showed he has the talent to do the same when it comes to the trajectory of this rebuild.

“We fought against a very good team tonight,” Kevin Love said. “We gave a lot of effort and KP was probably our best player.”

And, remember, as Nance said twice: Porter’s only 19.

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