[/media-credit] Cleveland Cavaliers’ Isaiah Thomas (3) passes against Portland Trail Blazers’ Damian Lillard (0) in the first half Tuesday, Jan. 2, 2018, in Cleveland. (AP Photo/Tony Dejak)

WALTHAM, Mass. — When Brad Stevens studied the video of Boston’s last game against Cleveland, he skipped over a handful of plays and put the sound on mute.
“I didn’t want to watch the injury or what happened after it,” the Celtics coach said on Tuesday, a day before his team was to play the Cavaliers for the first time since Gordon Hayward broke his leg in the season opener. “I just didn’t want to rehash that moment, obviously.”
Boston’s top free agent acquisition last summer, Hayward went down in a heap in the first quarter of the first game and is expected to be lost for the season. The gruesome injury cast a pall on the opener and upended the Celtics’ plans to supplant the Cavaliers as Eastern Conference champions.
“It was the first game of the season,” forward Jaylen Brown said. “When Gordon went down, it was a traumatic moment for everybody.”
But the game — and the season — went on.
The demoralized Celtics erased an 18-point, third-quarter deficit in the opener before losing by three. After falling to 0-2 with a loss in their home opener, they ran off 18 wins in a row, and now enter the new year 30-10.
“This team’s really getting after it, really playing well,” Al Horford said. “We never expected this after Gordon going down. It’s really a good surprise.”
Boston held a four-game lead over Cleveland in the race for the conference’s No. 1 seed, pending the Cavaliers’ matchup with Portland on Tuesday night, when former Celtics point guard Isaiah Thomas was scheduled to make his season debut after missing the first seven weeks with a hip injury.
“He’s a special guy,” Stevens said. “It’s great to see him back on the court tonight.”
Thomas is not expected to play on back-to-back nights this early in his return. Celtics spokesman Christian Megliola said there would be no tribute video for Thomas “at his request”; Thomas said on Twitter that he wanted to hold off until he was ready to play, and have his family there.
The team will honor Thomas some other time, Megliola said. The Cavaliers also visit on Feb. 11, a night that has been set aside to retire Paul Pierce’s No. 34. The teams have met in the playoffs two of the last three years, and are the favorites to match up in the conference finals for the second straight year.
“They’re the team to beat. Everybody knows that,” Stevens said. “They haven’t even had Isaiah yet, and we all know how special he is.”