SHANGHAI — Atop the Ritz-Carlton, overlooking this city, Kyrie Irving huddled with Joe Tsai. The superstar who will lead the Nets locked in conversation with the billionaire who just bought them.

These are the moments Tsai cherishes.

With Kevin Durant out for most if not all of this season, the Nets will need Irving to live up to his all-NBA billing. The guard signed a four-year, $141 million contract this summer, and Monday night he met with the man who signs those hefty checks.

“I had a chat with him on the rooftop when we were taking photographs. It was a terrific conversation,” Tsai told The Post. “We talked a lot about a lot of things. I enjoy those conversations, but I don’t demand those conversations. I think they come naturally.”

Irving, Durant and Spencer Dinwiddie have all made regular trips to China on off-court business. But this time their business is on-court, playing sold-out games against the Lakers on Thursday here and Saturday in Shenzen.

Tsai, who bought the Nets from Mikhail Prokhorov in August, was in New York when Durant and Irving decided to join the Nets. But the Alibaba co-founder lives primarily in Hong Kong, so he isn’t around the team as much as some NBA owners.

So he relishes the time he does get to spend with the players; he just doesn’t demand it.

Tsai said he got to know Joe Harris this summer after spending time with him first during the 3-point champion’s trip to the UEFA Champions League final in Madrid — they ended up running into each other in the same hotel — and again during Team USA’s stay in China for FIBA World Cup.

With all the Nets in China now, Irving will have a “nice sit down” with Tsai and his philanthropic investor wife Clara, as they get to know him better.

“I know that we’ve got incredibly popular players. It’s not like the minute we sign them I call up [GM] Sean Marks and say I need KD’s phone number,” Tsai said. “I’m very respectful of their space. At the appropriate time I want to sit down with KD.”

Durant didn’t make the trip, left back in Brooklyn to rehab his ruptured Achilles. The performance team thought it wise to take a pass on the 16-hour flight to Shanghai, and all the resulting jet lag, fatigue and other elements he would have to deal with.

But the rest of the Nets trekked halfway around the world from Brooklyn, and Tsai couldn’t help but take notice of the bond they showed when they finally got there.

“The players got in late, so we had an open buffet kind of setting so they could just come in, grab some food and go to sleep,” Tsai said. “What I observed, the chemistry, the camaraderie around the team is incredible. They’re talking to each other, they seemed comfortable with each other, having fun.

“This is after a long, what, 16-hour flight? I would’ve been, ‘Forget it, I’m going to sleep.’ But they were hanging out. It’s important to have that chemistry, especially this early in the season. We’re more than half a new team. To see them — not just the original players, but the new guys — was [good].”