Now, the point-guard competition can truly begin.

After missing the Knicks’ first two preseason games with a strained lower back, Dennis Smith Jr. was a full participant in Sunday’s practice and appears likely to return for the team’s next preseason game, Wednesday against the Hawks at Madison Square Garden.

“He’s doing what he left off doing, which is really competing defensively, pushing the pace, attacking, organizing us,” coach David Fizdale said. “He had a really good practice.”

Following two preseason starts from Elfrid Payton — who shot 0-for-9 from the field in Friday’s 115-99 blowout loss to the Wizards — Fizdale wouldn’t commit to starting Smith at the point in the next game.

But the coach hasn’t hidden his belief that the third-year guard’s first full season with the Knicks should be Smith’s finest.

“Everything I asked him to be better at, I felt like he was showing signs of being better at,” Fizdale said of Smith’s training camp. “Whether it was his conditioning, his shooting or getting us organized and making plays for other people. Hopefully we can keep that going and pick up where he left off.”

Payton, a fellow former lottery pick, was limited to 42 games last season but averaged 7.6 assists with the Pelicans, and has averaged 6.6 per game in his first five seasons.

Smith averaged a career-best 5.4 assists in 21 games with the Knicks last season, and the 21-year-old expects them to come even easier with a deeper, more experienced team.

“We got some really good pieces around us this year, some guys who can really score the ball. I feel like it’s easy to set these guys up,” Smith said. “I got better at it. What’s so funny is I don’t even know where that story came from that I’m trying to score all the time.”

Smith might never play like a traditional point guard, but his coach isn’t asking that of him. After arriving from Dallas in the middle of last season, Smith averaged 14.7 points, while shooting 41.3 percent from the field.

“I feel like he can be a point guard. You’ve got to remember, in our league now, the point-guard spot is a scoring position,” Fizdale said. “I think it’s more scoring points now than it is distributors. He fits that mold of being a scoring point guard.”

Smith’s ceiling is most easily envisioned on offense, but Fizdale said he thinks the guard’s greatest room for growth could come on the other end.

“You’re talking about one of the best athletes in the NBA,” Fizdale said. “If he can put together a real tenacity with that and a technical focus with it, he can absolutely become a better defender.”

The Knicks’ most important return for Kristaps Porzingis can still become anyone. He is just 21.

“It was super tough, especially being in Dallas with a team that’s a lot older, and then coming into our team with the Knicks. At one point we were the youngest team in the history of the league,” Smith said. “But smooth waters never made a steady sailor. I took the adversity head on, and I’m looking forward to having a good year this year.

“I feel like I paid my dues this summer and earned the team’s respect, and now it’s all about putting it together.”