RIVERSIDE, Calif. >> Victory becomes easier when the opponent sabotages itself, as Hawaii witnessed Friday night in Big West Conference volleyball.

The Rainbow Wahine exploited UC Riverside’s numerous mistakes in a 25-16, 25-17, 25-22 sweep at the Student Recreation Center Arena.

UH (12-6, 8-1) used its third consecutive victory to remain a half-match behind first-place Cal Poly (18-1, 8-0). The 12th-ranked Mustangs swept Cal State Northridge on Friday to remain undefeated in conference play.

The Wahine conclude their road trip at Cal State Fullerton (6-15, 0-8) today (4 p.m. Hawaii time).

Riverside (6-13, 1-7) entered the match without perhaps its best player: senior outside hitter Ka’iulani Ahuna, who led Kamehameha-Hawaii to four Big Island Interscholastic Federation championships. Ahuna has not played since twisting her right knee Sept. 18 in Set 1 against Long Beach State, yet still ranks second in the Big West with 5.07 kills per set and holds fifth place with 213 kills.

Without Ahuna, the Highlanders hit just .114 for the match — .056 in the first two sets, minus-.029 in the second set alone.

“I think when the other team is making those errors, we definitely need to take advantage of that and force the errors, instead of ourselves making errors,” said McKenna Granato, who finished with 10 digs, two aces and a match-high 12 kills. “It definitely brings a lot of momentum to our side.”

It was the ninth double-double on the season for the senior hitter whose first ace of the match gave her 100 for her career.

That momentum proved pivotal in the first two sets. The hosts held a 9-8 lead in Set 1 when UH used an 8-2 surge to move ahead, 16-11. Three of the Wahine’s points came from hitting errors, with two more resulting from long serves. Out of those five errors, the Highlanders committed three in succession.

In Set 2, Riverside built a 6-2 advantage but UH turned two service errors, a spike that sailed wide off a quick set and a double-touch violation into four points, and senior opposite Angel Gaskin and senior middle Sarah Liva combined on a block to force a 7-7 tie.

At 9-9, a 4-0 burst gave the Wahine a 13-9 lead. Gaskin and Granato contributed kills during that spree, with junior middle Natasha Burns converting off a quick set by senior setter Faith Ma’afala.

Hawaii took a 2-0 lead when scoring seven of its final 12 points on the Highlanders’ hitting and service errors. Many of Riverside’s mistakes could be attributed to numerous adjustments the hosts made since their 25-15, 25-19, 25-17 loss at the Stan Sheriff Center on Sept. 29, as they tried to avoid their eighth loss in nine matches.

“When we were watching film, we knew they made a lot of changes,” Granato said. “So we just had to remember each hitter’s tendencies instead of where they play.”

The Wahine needed Granato and Ma’afala to take control late in Set 3, a tight set that saw 10 ties and the lead exchanged four times.

“Every time we come here, they just play crazy defense,” UH coach Robyn Ah Mow-Santos said of the Highlanders’ 51 digs. “Their defense is unbelievable.”

With Riverside holding a 17-16 lead, Granato pounded a cross-court kill from the right pin to tie it. Ma’afala, using a hard serve with virtually no rotation, followed with the first of her two aces.

Granato then propelled a cross-court kill from the left side followed by a hitting error from Kat Lowry. Ma’afala ended the 5-0 spree with another ace, and UH owned a 21-17 advantage.

The Wahine committed 12 service errors and 13 hitting errors when running their record to 25-0 against the Highlanders.

“I think we made a lot of mistakes, too,” Ah Mow-Santos said. “My team always gets off to a slow start. But the warm-up was good. The play maybe could have been a little better but energy-wise, we were pretty good.”

Ma’afala finished with 20 assists, junior Norene Iosia added 18 assists and senior libero Tita Akiu had a match-high 19 digs when surpassing 300 for her UH career. Riverside’s freshman hitter Marissa Holt had a team-high nine kills and sophomore libero Nicole Rodriguez 14 digs.