Crescenta Valley (3-4) was led in scoring by junior guard Eric Strangis with 31 points.
Strangis, held to just one field goal in the fourth quarter, was finally slowed by the Cleveland defense when the Falcons needed scoring the most — in the final two minutes of the game with a double-digit lead all but evaporated.
After Carl Brackens hit a jumper to put Cleveland (6-2) up 66-65 with just under 30 seconds remaining, Strangis missed a contested short-range jumper.
He rebounded his own miss, but the putback attempt amid a horde of defenders also rolled off the rim.
Following two Cavaliers free throws, Crescenta Valley had one more chance to tie the game with 0:06 on the clock, but Strangis' three-pointer from the top of the key missed.
"I was getting good looks but they just didn't drop — that's how it goes sometimes," Strangis said.
The Falcons enjoyed several runs of momentum throughout the game, punctuated by defensive lapses which undercut a strong overall offensive effort.
Strangis got off to a fast start, scoring 11 points on five-of-nine shooting from the field.
Crescenta Valley built its lead up to 30-21 on an Izaac Dasaad three-pointer, with 2:00 remaining in the first half.
Cleveland closed the half with a 6-0 run, however, to trail by just three at the break.
The Falcons rebuilt the lead to 38-30 early in the third quarter on a pair of Strangis threes and a layup by Clayton Sierra.
Over five minutes of the third quarter had elapsed before Cleveland converted a field goal, a dry spell ended by Davion Parks' layup which cut the Falcons' lead to 44-34.
From there, the Cavaliers, who pulled down 15 offensive rebounds, never let up on attacking the Falcons' interior defense for easy baskets.
They stormed back to tie the game at 59 with three minutes to play, and took their first lead, 64-63, with 1:30 remaining.
"We allowed a lot of dribble penetration," Strangis said of the defensive breakdown. "Before the game we talked about taking a lot of charges because we knew [Cleveland] didn't shoot the ball well from the perimeter.
"Once they got in the key, we didn't go a good job [of that], and we let them get a bunch of offensive rebounds. It was really second-chance opportunities and easy baskets."
Crescenta Valley will be back in action on its home floor today at noon for a regional consolation game against Birmingham.
GABRIEL RIZK covers sports. He can be reached at (818) 637-3226 or by e-mail at gabriel.rizk@latimes.com.