Rivers is in charge of the LA Clippers, who the Lakers share the Staples Center with.
But he coached Rondo for seven of his nine seasons with the Boston Celtics.
The veteran play-maker joined the Lakers on a one-year, $9million deal in the summer.
But despite being across town at the Lakers’ rivals, Rivers insists he keeps in regular contact with the 32-year-old guard – who is thought to have had a positive impact on the team as a leader.
Rondo’s basketball IQ is renowned around the league and Rivers – who won a championship with the four-time All-Star in 2008 – believes he is the smartest figure he has encountered in the NBA.
And he also paid tribute to the impact that both Rondo and LeBron will have as a duo on the Lakers’ young core.
Asked about the Lakers while appearing on Skip and Shannon: Undisputed on Fox Sports, Rivers said: “LeBron’s been amazing. They’re young and they’re growing.
“They’re not to be discounted, I think they’re really talented and they’re really good.
“Having LeBron and Rondo, I think is so underrated from a leadership standpoint and a teaching standpoint.
“I’ve never coached LeBron but I have coached Rondo and he is the smartest, he’s a handful but he’s in a good way and he’s really grown.
“We talk so much now and his maturity has sky-rocketed.”
Asked about being in regular communication with Rondo, Rivers continued: “A lot, yeah. I talk to a lot of my ex-players. What people don’t get, the best part about coaching is maybe that.
“[You talk to] All the past guys you’ve coached, even when Rondo and I had an up-and-down relationship at times.
“At the end of the day we always communicated with each other and what I’ve learned with Rondo, you have to because he is the smartest guy I have ever been around basketball-wise.
“He studies like a coach. I think that is going to help the Lakers at the end of the day.”
Rondo is currently out injured with a broken hand but has recently been cleared for non-contact basketball activities.
The purple and gold’s assist numbers have dropped without the guard and coach Luke Walton said of his ongoing rehabilitation: “He’s very eager to get out and be in as much activity as he can so when he is fully cleared he’s not as rusty.
On their passing numbers, Walton added: “By the end of the season, we will be a team that is constantly making those extra passes.
“When you make the extra passes, your assists go up. It’s the way the game should be played.”