Celtics forward Jayson Tatum drives to the basket Wednesday night during Game 5 of a second-round playoff series against the Cleveland Cavaliers. Tatum had 25 points, 10 rebounds and nine assists in a series-clinching 113-98 victory. Charles Krupa/Associated Press

BOSTON — Jayson Tatum had 25 points, 10 rebounds and nine assists, and the Boston Celtics beat the Cleveland Cavaliers 113-98 on Wednesday night to advance to the Eastern Conference finals for the third straight season.

Al Horford added 22 points, 15 rebounds and six of Boston’s 19 3-pointers to post their third consecutive win of the series and earn a 4-1 series victory. The Celtics will now await the winner of the matchup between the New York Knicks and Indiana Pacers. New York leads that series, 3-2.

The Cavaliers played extremely shorthanded without All-Star Donovan Mitchell (calf), center Jarrett Allen (rib) and key reserve Caris LeVert (knee).

Cleveland stayed close through the first three quarters and pulled within 88-85 early in the fourth. Boston then went on a 13-2 run to take a 101-87 lead with 6:44 to play.

Evan Mobley scored a playoff career-high 33 points and had seven rebounds for the Cavs. Marcus Morris Sr. made five 3-pointers and finished with 25 points.

Cleveland now enters a summer of uncertainty, with the futures of Mitchell and Coach J.B. Bickerstaff squarely in the spotlight.

Mitchell averaged 29.6 points in these playoffs but didn’t play in either of the final two games. He’s eligible to sign a contract extension but has not given any indication he’s eager to stay or leave Cleveland.

Bickerstaff completed his fourth full season as Cleveland’s coach. Including the 11 games he coached after taking over for John Beilein during the 2019-20 season, Bickerstaff is 170-159 with two playoff appearances.

Much like they did in Game 4 without Mitchell, the Cavs used the 3-point line to keep pace with the Celtics, making 8 of 19 in the opening 24 minutes.

Cleveland started the second quarter by connecting on 4 of 5 attempts from beyond the arc to nudge ahead 46-40. The Cavs got solid minutes off the bench from Morris, who scored 14 points in his first 12 minutes of action.

But Boston rallied and closed with an 18-6 run to take a 58-52 lead into halftime.