The top-seeded Boston Celtics will open their Eastern Conference semifinal series on notice, as they face an opponent that already has expressed it has more to prove.

The well-rested Celtics and the stretched-to-the-limit Cleveland Cavaliers each will attempt to draw first blood when Game 1 gets underway Tuesday at Boston.

Boston advanced by beating eighth-seeded Miami in five games. Cleveland was pushed to seven games in its first-round series, getting Donovan Mitchell's 39-point performance as fourth-seeded Cleveland extended its season with a clinching 106-94 win over the visiting Orlando Magic on Sunday.

"This is why I'm here," Mitchell said. "It's my job.

"I don't mean this disrespectful, but it doesn't really mean much. We didn't come in just to win the first round. We accomplished one goal, now we have to do it again. That's the mindset."

Mitchell, who has been dealing with a left knee injury all season, scored 50 points in a Game 6 loss at Orlando. He has scored at least 30 points in 23 of his 52 career playoff games,

"That's what special players do when it matters most," Cleveland coach J.B. Bickerstaff said. "He was special when he needed to be."

Both teams are expected to be short-handed. Boston center Kristaps Porzingis is likely to miss the entire second round with a right calf injury the he sustained during the series against Miami.

"It's something, not nothing, so it will take a little bit of time, for sure," Porzingis said. "But I'm doing everything I can to speed it up because I want to be back out there as soon as possible. But understanding, like, the worst thing would be probably to reaggravate that. So being smart.

"You would have to ask the medical people about the specifics of it. I'm kind of just following the plan. But I'm hoping for a return as soon as I start to get better."

Cleveland center Jarrett Allen has missed the last three games with a rib injury. Allen averaged career bests with 16.5 points and 2.7 assists along with 10.5 rebounds in 77 games during the regular season. He averaged 17.0 points and 13.8 rebounds in four playoff games against the Magic.

The Cavaliers overcame an 18-point first-half deficit in Sunday's clinching victory.

"We showed a lot of fight," Cleveland's Caris LeVert said after scoring 15 points off the bench in Game 7. "We showed what we've been showing all year long. We just kept fighting.

"We've been there several times this year, not just games, just as a unit. We've been banged up. We've been injured. But we got a next-man-up mentality and we just never quit."

The Celtics won two of three meetings with the Cavaliers during the regular season. Mitchell didn't play when Cleveland earned a 106-105 victory at home March 5. The Celtics prevailed 120-113 and 116-107 in back-to-back games played at Boston in December.

Game 2 in the best-of-seven series will be played Thursday at Boston. The Celtics are trying to reach Eastern Conference finals for the third straight season, with the Cavaliers not shying away from the challenge.

"We know who we are - a team that's a contender," Mitchell said. "We did what we're supposed to do. In the grand scheme of it all, we just took seven games. So for us coming into Boston, I'm pretty sure everybody thinks they're going to come in and kick our ass. We just need to be who we are."

--Field Level Media

Quickchart Matchup

Cleveland Off vs  Boston Defense
111.3 Points For 108.3 Points Against 47.6 FG% 45.2 FG% 43.1 Reb 42.9 Reb

Boston Off vs  Cleveland Defense
119.8 Points For 109.4 Points Against 48.6 FG% 46.0 FG% 46.3 Reb 42.9 Reb