Kemba Walker, Evan Fournier, and Evan Fournier are the Knicks backcourt starters. They have played with the Nets less frequently than their Knicks colleagues. 

As Boston’s starting backcourt, Walker and Fournier battled the Nets in the first round last May, losing in five games. 

This was before Kyrie Irving’s ankle sprain in Milwaukee ended his 2020-21 season. This was before Irving’s controversial decision to go unvaccinated against COVID-19 that could end Irving’s 2021-22 season before it begins. 

Their rivalry growing, the fully vaccinated Knicks visit Brooklyn to face the first-place Nets on Tuesday in their season’s first meeting. They no longer play in preseason — part of the rivalry’s intrigue. 

“With Boston, they were really good,’’ Fournier said. “Kyrie was playing. I mean, let’s be honest, if Kyrie and James Harden don’t get injured, they probably win it all. Their skills can make them very competitive. Their loss against Phoenix is disappointing. [Saturday], so they’re going to be motivated against us.’’ 

Fournier has heard from teammates what it’s like to be a Knickerbocker playing inside Barclays Center. Yes, it’s Garden East. Or better yet, Garden East River. The Nets won three of the last season’s meetings but there were very few people or none at all. 

Tuesday’s game is part of the Knicks’ current six-game gauntlet in which they also will have faced the Bulls twice, the Lakers, Suns, Hawks and Nuggets. 

“Obviously, we have a tough schedule ahead,’’ said Fournier. “I think we all know that. I’m new here, so I don’t know how much of a factor Nets versus Knicks is. I guess I’m going to find out. It’s good for the fans. Let’s say that.’’ 

The Knicks stand at 11-9 following their big 99-90 upset win Saturday over the red-hot Hawks — perhaps a night that can change the complexion of their season. They didn’t have Kemba Walker, Derrick Rose, Nerlens Noel and Taj Gibson. Rose should have been back Tuesday for the Knicks. 

“[Will it] give us momentum?’’ Fournier asked. “We’re going to find it out. Every win builds momentum and gives you confidence. You must be consistent. It is important to keep the positive things going and continue doing them over. This can help us build momentum and allow us to win more games. We just have to bring it every night.” 

Tom Thibodeau was pleased with Jericho Sims, the Knicks rookie center in Atlanta. Sims, the 58th selection in this draft, had six points. He was a plus-14 — second-best on the club — as he got paired with summer league teammates Obi Toppin, Immanuel Quickley and Quentin Grimes on an effective unit. 

“His athleticism, reaction to the ball, rim protection, he can go get rebounds in traffic and the way he runs the floor,’’ Thibodeau said in listing what he likes about Sims, a Texas product. “That [young] group can play fast and they did.’’