The Suns, who looked as though they were about to get run out of the building, rallied from an 18-point halftime deficit by dominating the final two quarters for a 99-90 win Sunday night.
"We were getting embarrassed," said Markieff Morris, who led Phoenix with 27 points. "Everybody knew it. That's why we said if we were going to lose, we were going to go down fighting."
Cleveland coach Mike Brown had a simple assessment of his team's meltdown.
"It was hard to watch," he said. "It's disappointing we came out and played that way, and we should all feel embarrassed for the way we played in the second half."
The Suns held Cleveland to six points in the third quarter and outscored the Cavaliers 56-29 in the second half. Channing Frye finished with 16 points, including four 3-pointers after halftime, and Goran Dragic scored 15 to help Phoenix rally on the first stop of a four-game road trip.
"We were so, so bad in the first half, but at least everyone knew how bad we were," said Suns forward P.J. Tucker, who had 13 points and 10 rebounds. "When we were down, everyone was like, `We're good.' That's the kind of faith we have in our team, but we can't keep doing this."
The Cavaliers, who led by 20 late in the second quarter, fell to 1/3 on a five-game homestand considered crucial to their chances of staying in the Eastern Conference playoff race.
"They outworked us in the second half, simply put," said All-Star point guard Kyrie Irving, who led Cleveland with 24 points.
Cavaliers center Anderson Varejao injured his left leg late in the fourth quarter. He was down on the court for several minutes, but remained in the game. Varejao, who has battled injuries the last three seasons, will be checked by the team's medical staff on Monday.
"I was worried," Brown said. "His knee was bothering him a little bit. It was tough to see."
Phoenix trailed 61-43 at halftime, but hit five 3-pointers in the third quarter. Tucker scored on an offensive rebound with 45 seconds left to put Phoenix ahead 68-67, its first lead since 9-6 just 4 minutes into the game.
The Cavaliers were 2 of 22 from the field in the third and set a season low for points in a quarter. Cleveland's 29 points after halftime marked a season worst for a half.
"I got on their case at halftime because we didn't give effort in the first half," Suns coach Jeff Hornacek said. "It was the defense that did it. We got stops and that started it. Then all of a sudden, the other team was back on their heels."
The Suns broke away from a 70-all tie with 11 straight points early in the fourth. Leandro Barbosa's free throw put Phoenix ahead for good. Morris scored six points in the run before Barbosa's steal and layup made it 81-70 with 8:38 remaining.
Irving's two free throws with 2:06 to play cut it to 88-85. The teams traded baskets before Frye's 3-pointer made it 93-87 with 1:14 remaining.
Phoenix shot just 39 percent in the first half, when its starters combined for 24 points. Morris scored 15 off the bench.
The Suns came out firing in the third quarter, forcing Cleveland to call timeout twice in the first 5 minutes. Frye hit 3s on three straight possessions, Gerald Green added a 3-pointer and a jumper, and a 3 by Dragic helped cut the lead to 65-61.
Phoenix trimmed the lead to two on two occasions. Ish Smith's free throw with 1:13 remaining made it 67-66 before Tucker put the Suns ahead.
Cleveland ended the second quarter on a 22-10 run sparked by Luol Deng's 10 points and six by Irving. The Cavaliers led 39-33 with 7:39 remaining in the period when Deng hit two jumpers, a layup and four free throws. He also found Jarrett Jack in the corner for a 3-pointer with a pass from the top of the key. Irving added a pair of jumpers and two foul shots.
Irving had 13 points and seven assists in the first half. The third-year guard, elected an All-Star starter for the first time last week, had six assists in the first quarter, including Cleveland's first four baskets of the game. Deng had 12 points, six rebounds and four assists in the first half.
The Suns opened a road trip in which they will play four games in five nights. Phoenix went 1-4 on a trip earlier this month.
Suns G Eric Bledsoe (right knee surgery) is traveling with the team, but there remains no timetable for his return to the court. Bledsoe, the team's leading scorer, averaged 18 points in 24 games before undergoing an arthroscopic procedure on Jan. 10. ... Deng had his first double-double for the Cavaliers with 18 points and 10 rebounds. ... Phoenix recalled G Archie Goodwin from his NBA Development League assignment with Bakersfield. ... Cleveland brought back F Sergey Karasev and G Carrick Felix from their D-League assignments with Canton.