Given that Kyrie Irving and Gordon Hayward are sidelined, the Celtics deserve a ton of credit for having defeated lower-seeded Milwaukee in the opening round and lower-seeded Philadelphia in the quarterfinals. The person most responsible for the Celtics’ staying power is not necessarily any of the healthy players but, instead, the head coach.

Brad Stevens, 41, is fantastic at what he does. Of this there is no dispute. He has carried the undermanned Celtics to the doorstep of the NBA finals. His motivational tools, offensive and defensive systems and out-of-bounds plays are the envy of the NBA coaching fraternity.

Meanwhile, on the other side, Cavs Coach Tyronn Lue long ago dropped his compass in the locker room. Stevens vs. Lue is Mike Tyson vs. Marvis Frazier.

In three seasons, Lue has coached in 50 playoff games and won a mere 37 (.740 efficiency). He has coached in 10 playoff series and won just nine (.900 efficiency). He has coached in two NBA finals and won only one, the latter allowing him to become the first coach of a major pro sport in Cleveland to win a title since 1964.

Lue, 41, has done nothing but spectate while LeBron James has carried the Cavs. The ego-less, agenda-less Cavs coach themselves.

Even though the Cavs have LeBron, the Celtics’ enormous advantage at head coach might be enough to push them into 2018 NBA finals.

“I think they are one of the most well-coached teams in our league,” James said.

As far as Brown is concerned, he’s moved beyond the minutes restriction that was in place to help him recover from a strained right hamstring. No one was helped more by Thursday’s off day than the Celtics swingman.

“These days of rest have really helped me a lot. I’ll be 100 percent ready,” he said.

“(You) got smarter with your movements and stuff like that,” Brown added. “It was kind of weird, because my body was reteaching itself how to run. I’m happy that I played through it because we got the wins that we needed, but now it’s good to get some rest and get ready for Cleveland.”

When he’s standing in attention for the national anthem at TD Garden Arena, LeBron James will look up and see the retired jersey numbers of Bill Russell, Sam Jones, Tom Heinsohn, and Frank Ramsey.All of them Celtics, they are the only players in NBA history with more consecutive Finals appearances than James’ current streak of seven. If James and the Cavs beat the Celtics in this series, James will tie Ramsey.

Jones and Heinsohn went to nine straight Finals and Russell holds the record with 10 consecutive berths, from 1957-66.

George Hill has gone from point guard to point grad in the NBA playoffs.

Cleveland’s starting guard was excused from practice on Saturday to receive his degree from IUPUI. As his Cavaliers teammates got in one last workout before heading to Boston for Game 1 of the Eastern Conference finals, Hill took part in graduation ceremonies at the school in Indianapolis.

The 32-year-old Hill received his degree from the School of Liberal Arts. He was one of two student speakers to address the new graduates. Hill played for the Jaguars from 2004-08.

Lue said Hill would rejoin the team in time for the series opener Sunday against the Celtics.

Hill joined the Cavs in February, coming over in a trade from Sacramento.

He was slowed by back spasms and missed three games in the first round of the playoffs against Indiana. But he returned and played a key role in Cleveland’s four-game sweep of Toronto.

The Atlanta Hawks are hiring a young coach in Lloyd Pierce to lead a rebuilding team that is about to add even more youth.

The Hawks announced they are giving Pierce his first head coaching job in the NBA, choosing a man who has been an assistant with Philadelphia and Memphis to rebuild the franchise.

Pierce, 42, spent the past five seasons as an assistant coach in Philadelphia where the 76ers just reached the Eastern Conference semifinals after finishing third in the conference with a 52-30 record.

Pierce also spent two years as assistant coach with Memphis Grizzlies, including 2013 when they reached the Western Conference finals.