James Harden had 34 points, 10 rebounds and 10 assists for his first postseason triple-double with Brooklyn, leading the Nets into the Eastern Conference semifinals with a 123-109 victory over the Boston Celtics on Tuesday night in Game 5.

Kyrie Irving scored 25 points and Kevin Durant had 24 for the Nets, who will face the Milwaukee Bucks in their first appearance in the second round since 2014. The No. 2-seeded Nets will host Game 1 on Saturday.

Despite their limited time together during the regular season, the Nets’ three superstars showed how potent they can be in this series, particularly when they combined for 104 points in Game 4.

Brooklyn was nowhere near as potent as that game, when it rang up 141 points. But a little explosive stretch here and there was good enough to wrap it up.

The finishing one came with the Celtics trailing by just eight with under eight minutes to play. Durant then made a 3-pointer, Jayson Tatum turned it over and Irving nailed another 3 on the break, pushing it to 103-89 with 7:19 to play.

Evan Fournier scored but Harden answered with another 3 and Bruce Brown scored inside, an 11-2 burst in less than 90 seconds that broke it open at 108-91 midway through the fourth.

Tatum had 32 points and nine rebounds for the Celtics, who made the Eastern Conference finals last year but went quickly with Jaylen Brown and Kemba Walker unavailable.

Fournier added 18 points and Romeo Langford had 17 starting in place of Walker, who missed his second straight game with a knee injury.

The Nets were eager to avoid a return to Boston after a fan threw a water bottle at Irving after Game 4, but the clincher didn’t come easily.

The Celtics hung in the game, not letting the Nets build a double-digit lead until a 7-0 burst early in the second half made it 66-54. Boston recovered and trailed just 86-79 after Tatum made a jumper at the buzzer to end the third.

TIP-INS

Celtics: Robert Williams also missed his second straight game with an ankle injury. ... Marcus Smart scored 14 points but was 1 for 10 on 3-pointers.

Nets: Jason Kidd has the other 10 triple-doubles in Nets postseason history. ... The Nets are 12-3 against the Celtics in playoff games.

IRVING’S INCENTIVE

Nets coach Steve Nash said he hadn’t talked to Irving much about what the opportunity to eliminate his former team from the playoffs meant to him. But Nash recalled there be an extra edge for him when he went to Phoenix and beat Dallas in the 2005 postseason.

“I don’t know if he feels the same way to be honest, but there is a little bit more to it,” Nash said. “For me, I spent six years in Dallas, six very important and impressionable years, influential years in my career. So there was a lot of kind of awkward, strange feelings in that experience.”

WALKER’S WOES

Boston coach Brad Stevens said Walker’s problem was a bone bruise, making it different than the soreness that bothered him last year in the bubble, delayed his start to this season by nearly a month and contributed to him playing in just 43 games.

“I sat down with Kemba in my room today for a while and told him how badly I feel for him and how much we just want him to feel better,” Stevens said.