The fans at Newark’s Prudential Center booed Donnie Walsh’s final career first-round draft pick last night. They should have been chanting “De-fense.”

The outgoing Knicks president has always been a defensive-minded basketball executive. Before he leaves for Indiana and retirement on July 1, Walsh put his final stamp on the Knicks by finally bringing in a much-needed point guard and defensive-minded player — elements Mike D’Antoni’s club desperately needs.

The Knicks, who are concerned about Chauncey Billups’ durability and defense at age 35, selected 6-foot-5 Georgia Tech junior Iman Shumpert with the 17th pick, hoping it works out better than the last time a Yellow Jacket playmaker ran the Knicks — Stephon Marbury.

Shumpert is big, physical and athletic, and he shot lights out during his workout earlier this month, allaying fears of him being a bad outside shooter (27.8 percent from 3-point land as a junior).

Shumpert had a vertical jump of 40 inches and outplayed Hofstra’s Charles Jenkins during the Knicks’ workout.

“He’s very good defensively, very athletic,” Walsh said. “He’s got a good package. I think he’s ready to play and he should make the rotation next year.”

Known as a defender, Shumpert’s shooting at the Chicago combine and during his drills in Westchester raised his stock.

“He had a great workout and he’s had great workouts,” Walsh said. “He shot extremely well. His shot’s not broken. Some guys you see, and you’re unsure if they can shoot. They have to learn it. He has good form. He was hitting shots. He can defend very well. He’s got tremendously long arms.”

Walsh’s choice came down to two defensive guys — Florida State forward Chris Singleton and Shumpert. Some in the organization felt Singleton was the best player available, but Walsh chose the latter because of position. The Knicks are thin in the backcourt and Shumpert can also defend shooting guards.

“Internally we talked about that a lot,” Walsh said of the choice between Singleton and Shumpert. “Fact is, we’re going to have more room at the [point guard] position and 2-guard position than the guys we have at the 3 and 4. I know people say [Singleton] can play [against shooting guards] but it’s difficult for guys that size.”

Shumpert averaged 17.3 points as a junior, but wasn’t a big name, partly due to Georgia Tech’s recent mediocrity. In fact, 10 days ago when Marbury was asked about Shumpert, he admitted he had never heard of the kid.

“If we want to become a better defensive team, we have to acquire better defensive players,” said Knicks interim president Glen Grunwald. “We think he can help us improve on that end of the floor.”

The Knicks were searching for a chemistry guy who would fit in well with Carmelo Anthony and Amar’e Stoudemire. Once USC center Nikola Vucevic was taken by the Sixers at 16, there wasn’t a big man of note left, the club having crossed undersized rebounding machine Kenneth Faried off their list after the Chicago combine.

“We got two guys who need the ball and are going to get the ball a lot of the time,” Walsh said. “We wanted people to complement that. In the Finals that’s what people were talking about — having all the pieces together.”

With Singleton, a projected lottery pick on the board, the Knicks fans were hoping for the athletic forward whom some on the Knicks’ staff viewed as a LeBron James stopper and the best overall player available.

Walsh acknowledged the boos.

“I came into this league with everybody booing me when I took Chuck Person, who was rookie of the year, and Reggie Miller the next year and I’m going out with everybody booing me,” Walsh said. “And that’s a good sign.”

Shumpert and Singleton were in the same workout group in Westchester.

“Just wanted to show I could fit into a team and play for the city, that I could play alongside guys like Melo and Ama’re,” Shumpert said after the workout. “I proved I can handle the ball, shoot the ball and be that knock-down guy in the corner. I shot well. I impressed everybody.”

Shumpert, who will meet the media today in New York, watched the draft from Chicago because he was not invited to the lottery’s green room.

As expected, Walsh purchased a second-round pick — No. 45 — from New Orleans and drafted Kentucky center Josh Harrellson, a 6-10, 275-pounder who averaged 7.6 points and 4.7 rebounds — though he nearly doubled the scoring average in helping the Wildcats to the Final Four.

Before the pick, Walsh said he did not feel there was a center available to help right away. Harrellson was once banned from Twitter for criticizing John Calipari.

***According to a source, Knicks inquired about Raymond Felton in last few days before he was traded last night from Denver to Portland…Walsh said with the draft over, he plans on turning his attention to extending Mike D’Antoni’s assistant coaches and some of his scouts.