By Marc J. Spears, Globe Staff

During the summer of 2006, then-Kentucky sophomore guard Rajon Rondo was given a phone number to a reference for the agent he eventually hired, Bill Duffy. But this wasn’t your usual reference. Rather, it was a Phoenix Suns point guard who was coming off his second straight NBA Most Valuable Player award, Steve Nash.

All Rondo was expecting was some nice words about Duffy in a short conversation. But by the time the current Celtics point guard hung up the phone, Nash left the youngster with words of wisdom, too.

“I told him to continue to work hard and have a long plan,” Nash said before last night’s 104-87 Celtics romp over the Suns at the Garden. “Obviously, whether it’s his shot and game in general, players have to have a long-term approach and remember whether you have a great rookie year or not, you want to be a pro for 10-15 years. You want to be a great player two or three years, if not four or five years. I just told him with hard work anything is possible. Obviously, if I could be in the position I am now from where I came from, he could do it, too.

“I just called him to let him know how I felt about Bill Duffy and tried to encourage him. It’s actually been great to watch a young player come into the league and improve the way he has.”

Nash scored 12 points and had 8 assists last night; Rondo went for 23 points and added 7 assists as the Celtics cruised.

Nash’s story is something that Hollywood could end up putting on the silver screen one day and one Rondo respects.

Nash was an unknown Canadian prep basketball star in Vancouver, where hockey is king. The only Division 1 basketball scholarship he got was to Santa Clara University. Considering that he was far from a stellar athlete, playing in the NBA didn’t seem in the realm of possibility when he arrived in the Bay Area. But after surprisingly shining with the Broncos and making a name for himself during three NCAA Tournament appearances, the Suns took Nash with the 15th overall pick in the 1996 draft.

It wasn’t until Nash’s fifth season that he showed star promise, then with the Mavericks, and he didn’t become an All-Star until 2002. Today, the 6-foot-3-inch, 195-pounder, who returned to Phoenix as a free agent after the 2003-04 season, is a six-time All-Star and one of the best Cinderella stories in NBA history.

“He told me to just work hard,” Rondo said about Nash’s phone advice. “He told me about the beginning of his career as a young player and how he wasn’t the man. But he continued to work hard and it eventually worked out. He found a home in Phoenix and he’s been the man for a long period of time.

“He’s had a great career. He’s been an MVP twice. He’s been [an] All-Star. He’s had a great career.”

Like Nash, Rondo didn’t enter the NBA with a lot of fanfare either.

The Suns actually took Rondo with the 21st overall pick in the 2006 draft, but dealt him on draft night to Boston with Brian Grant for a future first-round pick. Rondo averaged just 11.2 points, 6.1 rebounds, and 4.9 assists during his sophomore season at Kentucky, his final year with the Wildcats, and was far from an All-American.

But what Rondo had that Nash didn’t was baseball glove-like hands, dunk contest athleticism, and defensive back-like quickness. With such physical attributes, Nash could understand why Duffy wanted Rondo so bad.

“I’ve always been an underdog,” Nash said. “So I’m sure he’s the same way. He probably has that mentality, too, where he always has to prove something. I think that helps. He has a lot of great tools and as he develops that mentality is what will allow those tools to develop.”

After a so-so rookie season, Rondo averaged 10.6 points and 5.1 assists while living up to the pressure as the starting point guard for the now-defending NBA champions and played on the sophomore team at the Rookie Challenge game. He is now considered one of the NBA’s best young point guards and is a candidate for the Eastern Conference All-Star team as a reserve.

“I knew the type of skills he had and what he brought to this level,” Nash said about Rondo. “But you never know how it turns out. I’m impressed. I’m greatly impressed with the way he’s improved every season. And it looks like he is going to continue to improve.”

Along with being underdogs, Nash says the other things that he and Rondo have in common are “unselfishness and teamwork.” On the flip side, Nash also noted that Rondo is a “phenomenal athlete” and they play “a different way.” But one advantage Nash has over Rondo is an intimidating 3-point shot and a reputation for hitting big shots.

Rondo hits only occasional 3-pointers and his mid-range jumper isn’t considered a sure thing. He does, however, have the required work ethic and has listened to teammate Kevin Garnett’s advice by taking extra jump shots after every practice. If Rondo somehow can get a jumper close to Nash’s and similar consistency with his play, he instantly would be spoken about in the same breath with the NBA’s two top young point guards, Chris Paul and Deron Williams.

When asked what Rondo could learn from Nash, Celtics coach Doc Rivers said, “I’ll take [Nash’s] shot. That’s pretty good. Really, every night Steve’s agenda is to make his teammates better. And he does it every night. He does it some nights by scoring and passing. Other nights he decides to be a ball mover and does it. But that’s what Nash does every single night. He always does that.

“The one thing that Rondo can learn from Nash is Nash may not play well every night, but he doesn’t have an off night. He has a great mental focus every single night. He does it every night. I’ve never seen him play in a game where he has no focus or low focus. Young players, in general, are up and down in that.”

Rondo is just 22 now in his third NBA season; Nash was 22 when he got drafted. And with Rondo’s potential in mind, Nash won’t be surprised if Duffy starts asking Rondo to start taking those reference phone calls from aspiring NBA prospects soon, too.
“I love his game,” Nash said. “He’s not a shooter yet. But I think he can develop that and the rest of his game is great. He’s a terrific athlete. Terrific defender. Unselfish. He’s a winner. His passing has improved. He does all the little things. I’m a big fan of his game.”