The Grizzlies will face the Minnesota Timberwolves on Monday night in the title game. Minnesota beat Brooklyn 85-77 in the second semifinal.
Clarke had 23 points -- including four in overtime -- and 14 rebounds to lead Memphis. Tyler Harvey, whose 3-pointer tied it in regulation, added 13 points, and Bruno Caboclo had 12.
"We had some moments in the game today where we couldn't score, things weren't going the right way, we were trying [but] our legs were not there," said Memphis coach Taylor Jenkins, the only NBA head coach to also coach his summer league team. "[Brandon] was just being super verbal with the team ... I'm really proud of how he kept the team together. Obviously the plays he makes down the stretch are very impressive."
Clarke, who was taken with the 21st pick in the draft via a trade with the Oklahoma City Thunder, wasn't able to participate with the Grizzlies until the NBA cleared the deal and it became official July 6. In four games, he's averaging 12.5 points and 7.3 rebounds.
"It's pretty much getting off all that rust I kind of had on me," Clarke said. "It was tough at the start because I couldn't really do much with the team. Every time that I play basketball I want to win. I think that we all just kind of feel that as a team. Even though this is not like a real NBA tournament versus the big NBA dudes, we also want to win."
New Orleans reached the final four despite missing No. 1 overall pick Zion Williamson, who took a knee-to-knee hit in the second quarter of the team's first game on opening night and was shut down for the remainder of the league.
"We started this summer league off being about Zion Williamson; once he was out, then it became something different," New Orleans summer league coach Fred Vinson said. "This group really bonded together. They supported each other. Guys who were playing on the floor, guys who weren't playing on the floor, they supported each other. I wanted those guys to become a team."
TIMBERWOLVES 85, NETS 77
Naz Reid scored 20 points in 19 minutes in Minnesota's victory over Brooklyn.
"The goal since we even got here, trying to win everything," Reid said. "We knew it wasn't going to be easy, but we definitely have been able to take over this past week. I just want to continue that tomorrow."
Jordan McLaughlin added 12 points, and Mitchell Creek had 11 for Minnesota, the only undefeated team at 6-0.
"It's all credit to the players, and how they compete so far," Minnesota coach Pablo Prigioni said. "As coaches, we want to help them to become a championship team. This is summer league, but at the end of the day 32 teams show up in Vegas, only two [can] compete for the championship."
Jarrett Allen led Brooklyn with 15 points and 14 rebounds in 21 minutes.