This was not how Tyronn Lue wanted to receive his first NBA head coaching job after nearly seven years of preparation.

Beginning in 2009, Lue transformed himself from a former player to a coach in training, thanks to then-Celtics coach Doc Rivers, who told Lue in 2003 that once he was finished playing, the coach would save him a job on his staff.

Rivers assigned Lue some responsibilities as the Celtics readied for another title run in 2009-10. The job became a passion for Lue. In 2012, Rivers allowed Lue to coach the Celtics’ Las Vegas Summer League entry.

While the July atmosphere in Las Vegas is jovial and casual, with coaches replacing their suits with polo shirts, summer league coaching is actually a significant assignment and the first sign Lue was headed for a top job.

When Rivers took Lue with him to Los Angeles to join his Clippers staff, it was clear Lue was destined to be a head coach.

He’ll face the Celtics on Friday at Quicken Loans Arena as head coach of the title-contending Cleveland Cavaliers. It’s his eighth game as coach since taking over for David Blatt, who was shockingly fired after a 30-11 record and first place in the Eastern Conference.

Lue was handed the job and a multiyear contract, apparently the NBA-experienced coach LeBron James sought. Although the Cavaliers hired Lue and paid him handsomely to be a lead assistant before hiring Blatt, they had formed a close relationship before the firing.

Lue felt rather uncomfortable with the coaching change but has seized the opportunity. The Cavaliers are 5-2 under Lue but are coming off a surprising loss at Charlotte on Wednesday. Lue is calming down after the suddenness of the change.

“It’s a lot of thoughts,’’ he told reporters this week. “There’s a lot of stuff you have to put in and so much stuff you have to do. I wrote a lot of notes and went over them the next day.’’

That next day, a Saturday, when Lue addressed the media, he promised to be “better’’ than Blatt and to invigorate Kevin Love, whose production had been inconsistent and whose place in the offense was rather confusing. Love did not want to be a traditional “Stretch 4’’ in the Cavaliers offense.

But there he was, the burly 6-foot-10-inch, 250-pounder standing at the 3-point line to stretch the floor. Lue has emphasized that Love receive the ball more at the elbows — corner of the key — and score from the inside out.

Love is averaging 20.4 points in his past five games as the Cavaliers attempt to rise to the level of the best teams in the Western Conference. Cleveland is the prohibitive favorite to reach the NBA Finals but getting there would mean little if the Cavaliers get embarrassed by the Golden State Warriors — again.

The Warriors laid a 34-point beatdown on the Cavaliers at Quicken Loans Arena in a Jan. 18 game that marked the end of the Blatt era. General manager David Griffin’s decision to fire Blatt was heavily criticized around the league, with James assigned most of the blame for the fact the players were disconnected with the coach.

Lue relayed the message immediately that he was not going to serve as the buddy-coach to make LeBron and the rest of the guys feel comfortable. He said LeBron and Kyrie Irving were not in good enough shape to run a more up-tempo offense.

That multiyear contract gives Lue the security to make his own decisions and trust his own instincts. Seven months younger than Brad Stevens, Lue is one of the new younger NBA coaches — born in the mid to late 1970s — teams are beginning to trust.

The Phoenix Suns named former guard Earl Watson as interim coach this week. Watson is 36. Perhaps what Stevens has exemplified to NBA teams is that younger coaches are not exactly pushovers and perhaps more in tune with current players and more open to the analytical side of the game.

Lue has fresh ideas on how to improve the Cavaliers. He wants more passes on offense and less one-on-one play, despite the presence of the most unstoppable one-on-one player in the game. He also suggested the players actually participate in the pregame introductions at home because it engages the crowd more. Under Blatt, the players wouldn’t even acknowledge their intros.

It’s touch-and-go for Lue at this point. He is going to coach the Cavaliers his way and bank on his past experience and tireless work ethic to aid his progress. His rise has been rapid but there is a sense that the Cleveland organization is in better hands.

Sacrificing everything for the ultimate goal is the message Lue is trying to relay.

“Winning takes care of everything,’’ he said. “Winning two championships with the Lakers for me, people probably wouldn’t even know who I was. I was the 15th man that first year and people love me in LA. I was part of a team, part of a championship. It’s an unbelievable feeling.’’

Gary Washburn can be reached at gwashburn@globe.com. Follow him on Twitter @GwashburnGlobe.