Lance Thomas positioned himself behind the 3-point line just in front of celebrity row and let fly a jump shot that would swish through the nylon as the buzzer sounded to end of the first half of Monday’s night game between the Knicks and Warriors at the Garden.

The crowd roared its approval as the underdog home team took a 64-63 lead into the locker room against the defending NBA champions. It was a moment that was enjoyed while it lasted, which wasn’t very long.

The Warriors’ first possession of the third quarter offered an early indication how all this would turn out. Draymond Green put up his own 3-pointer, a desperation shot launched as the 24-second shot clock expired. The wild attempt bounced off the glass, then the rim and somehow went through the net, prompting a surprised shrug from Green. The Warriors had reclaimed the lead 66-64 and went on to an easy 125-111 victory. The Warriors outscored the Knicks 39-18 in a third-quarter reality check: Golden State is pretty good. The Knicks aren’t.

“We wanted to start the third quarter strong, but we didn’t do that,” Thomas said. “We let them get separation from us. They always come out in the third quarter ready to go and we weren’t ready for it.”

Look, no one is shocked by the final score, not with the Knicks playing without Kristaps Porzingis, who is out for the season with a knee injury, and Jeff Hornacek using a carousel of guards. What the Knicks gain from games like this are the lessons learned both good and bad.

The diamond in Monday’s rough performance was point guard Emmanuel Mudiay, scoring 20 points with 18 coming in the first half.

“I was determined to have a better game,” he said. “I’ve just been trying to figure at the system and get my shots off as well as get people involved. I just wanted to come out with an aggressive mentality.”

That’s a step forward. The step backward was how the Knicks approached the third quarter, knowing that’s when the Warriors do most of their damage. Instead of rising to the challenge, the Knicks wilted.

“The first half we were pretty good at least offensively,” Hornacek said. “We moved the ball well and we were looking for the open guy. In the third quarter it was how can I score?”

He pointed to the number of assists in the third quarter, which equaled just three after totaling 18 in the first half.

“When you have three assists, you’re not going to score,” Hornacek said.

It really wasn’t fair. The Warriors (47-14) are like the Michael Jordan Bulls, a group of traveling rock stars who appear before adoring fans all over the country. There were as many Golden State jerseys in the Garden as there were Knicks jerseys. By the second half, the Knicks looked like the Washington Generals trying to keep up with the Globetrotters.

“You have to be engaged for 48 minutes against them,” Mudiay said. “You can’t have three good quarters and one bad one. You’re not going to win like that.”

It’s hard for a team to put together 48 good minutes against the defending world champions when it is thinking more about next year. Heck, Mudiay barely knows the plays and he’s the point guard.

“I’m just trying to figure out what plays are good plays for me,” he said. “I’ve been working on that.”

Steve Kerr should be thanking the basketball gods each and every day he didn’t accept the Knicks heading coach job when then team president Phil Jackson offered it to him in 2014. Long story short, Kerr turned his back on the Knicks and became the Warriors head coach. He is now trying to win his third NBA championship in the last four years while the Knicks are laboring through another wasted season.

“This league is all about players,” Kerr said. “If you don’t have players, if you don’t have talented players and healthy players it’s hard to win.”

Hornacek knows all about that.