– Inside the Timberwolves locker room Saturday night, after the Wolves opened the preseason with a 109-100 victory over Miami at the Sprint Center, rookie point guard Kris Dunn was asked about his NBA debut.

Turns out he was a lot harder on himself than coach Tom Thibodeau had been moments before.

“If I were to grade it? Probably a ‘C,’ ’’ Dunn said. “Maybe a ‘C.’ ’’

Tough grader, Dunn.

As part of the second unit Saturday, Dunn played just over 24 minutes. He scored six points on 2-for-8 shooting, made one of two three-pointers and had seven assists to go with four rebounds. He also had four turnovers.

It was an up-and-down game that ended on an up note.

Entrusted with a lead entering the fourth quarter, the second unit finished the win after a slow start in the quarter’s opening moments. Over the final 12 minutes Dunn scored all six of his points and had three assists and two rebounds. His first basket was a 25-foot three-pointer with 7:09 left that gave the Wolves the lead for good.

First impression? Dunn is quick and strong enough to defend on the ball, he has the court vision to find open shooters. As he gets more comfortable, his ability to get into the lane should open up more shots for the likes of Nemanja Bjelica and Brandon Rush. He will, however, have to prove he can hit the open midrange shot.

Thibodeau liked that Dunn was productive despite not shooting great.

“Kris’ floor game was very, very strong,” Thibodeau said. “And his defense. He had good ball pressure, pushed the ball up the floor on offense. When you have that, that second unit can play effectively together.’’

Dunn, Bjelica, Rush, Shabazz Muhammad and Cole Aldrich formed the second unit Saturday. And, for the most part, they played well, especially with their spacing on the offensive end. The Wolves made 10 of 23 three-point shots. The second unit was 7-for-14 from behind the arc, with Rush hitting three of five and Bjelica two of five.

Much of that was because of Dunn’s ability to find the open man.

Thibodeau praised Bjelica’s aggressive play in the second half, liked Aldrich’s ability to protect the rim. Muhammad, Rush and Bjelica all scored in double figures.

And Dunn, as a rookie, at least held his own.

“I think he took the challenge,” starting point guard Ricky Rubio said. “He’s quick. He knows how to play. So he’s going to be fine. Sometimes he got a little crazy with the ball, he had a few turnovers. But, overall, he had a great first game as a pro.’’

All that and it’s only worth a “C”? Maybe it just shows that Dunn is willing to keep working at it.

“I think he was kind of nervous at first, in the first half,” Rush said. “But he kind of settled in. Once he got that three to go, that helped him out a lot. He’s going to be good. He’s a playmaker. That’s what he does. I’m glad I’m playing with him. He’s going to get me a lot of open shots.’’