PORTLAND — Once the Trail Blazers assured themselves of at least a .500 season with a victory in their home finale, Jarrett Jack dressed uncharacteristically in a slick suit and donned sunglasses in the locker room.

“He was supposed to get dressed up, too,” Jack said motioning at guard Brandon Roy, casual in jeans, as his other teammates chided him.

Such was the loose mood after Portland beat the Memphis Grizzlies 113-91 Tuesday night. While not in the playoffs, the Blazers showed they haven’t given up yet.

Roy had 16 points and 11 assists for the Blazers (41-40), who play their final game of the season today at Phoenix. Portland has not finished with a winning record since the 2002-03 season.

James Jones hit six 3-pointers to lead Portland with 20 points. Jack scored 18 points and Channing Frye added 16 for Portland.

Travis Outlaw punctuated the game with a pair of alley-oop dunks for the final margin, putting the sold-out Rose Garden crowd on its feet.

“We wanted to send the message to the fans that we’ve improved,” Portland coach Nate McMillan said. “We’ve gotten better and the next step is to make the playoffs next year.”

Hakim Warrick led Memphis with 17 points and 14 rebounds. Rudy Gay and Andre Brown each added 16 points.

The Grizzlies, coming off a 114-105 loss at home to Minnesota, finish the season with a visit to Denver today. That gives Memphis (22-59) one more chance to surpass last season’s NBA-worst 22 win-finish.

“This has been a frustrating season, a long season,” forward Brian Cardinal said. “We need a win, period.”

The Grizzlies were without veteran guard Mike Miller because of back spasms, and guard Javaris Crittenton, who has a sprained right thumb.

The Blazers decided on Monday to sit forward Martell Webster for the final two games. Webster was hospitalized briefly last week because of an irregular heartbeat, but had been cleared to play.

The Grizzlies lost all three games against the Blazers this season. Portland had not swept the team since 1998-99.

Memphis led by as many as seven points in the first half until Jones hit a 3-pointer to make it 39-38 for Portland with 6:67 left. After some back-and-forth scoring, Steve Blake’s four-point play extended the Blazers’ lead to 52-47.

Roy added a 3-pointer as the half ran out to make it 55-48.

Jones tried only four shots from the floor in the first half — all 3-pointers — and made them all. He attempted seven 3s for the game.

“Unfortunately we came out in the second half and we couldn’t hit shots,” Grizzlies coach Marc Iavaroni said. “That took a lot of wind out of our sails.”

Notes: Memphis rookie guard Mike Conley was teammates with Portland’s Greg Oden last season at Ohio State. The Buckeyes went 35-4 and faced Florida in the national championship game. Oden, the No. 1 draft pick last June, had microfracture surgery on his right knee that has sidelined him for the entire season. ... Portland radio personality Mark Mason announced his 500th straight game for the Blazers. ... The Blazers had seven players in double figures for the first time since Dec. 29, 2006.