"Turnovers are hard to swallow," said Glendale college Coach Brian Beauchemin, who saw the Vaqueros commit 13 second-half turnovers. "We just didn't do a good enough job with our ball possession.
"It's a difficult game to evaluate. We've got to win our home games."
Santa Monica (15-7, 5-2) jumped over Glendale into third place in the division and atoned for its 74-71 loss against Glendale on Jan. 8. Canyons had a bye Wednesday and Citrus competed against L.A. Valley.
The Corsairs received a game-high 22 points from guard Lee Lark.
The Vaqueros, who competed without starting guard Narbeh Ebrahimian, got 17 points from Sekamwa. Ebrahimian, a Crescenta Valley High graduate, missed the contest because of an illness.
Beauchemin said Ebrahimian's absence effected the Vaqueros, who saw their three-game winning streak halted.
"He was too sick," said Beauchemin, who got 15 points from Nate Bryant and 11 from Nikolas Rhodes. "He carries us, and, with him not in there, the matchups are different and there are a lot of lineup changes.
"Santa Monica's the type of team that makes you play fast. We got caught up with that in the first half. In the second half, we just didn't execute."
The Vaqueros cut the deficit to 78-75 on a three-pointer by Bryant with 57 seconds remaining. After Sekamwa's three-pointer with one second remaining didn't go, the Vaqueros fouled Deshawn Stephens, who made one of two free throws to clinch the win.
The Vaqueros, who have a bye Saturday, will next compete at 5 p.m. Wednesday against Citrus.