Jillian Alleyne posted her 28th straight double-double with 25 points and 16 rebounds, but a strong third quarter from No. 21 UCLA led to Oregon’s first loss the of the season, 80-69 in Los Angeles.

UCLA outscored the Ducks 28-12 in the third quarter after Oregon had a 39-35 lead at halftime.

Jacinta Vandenberg tallied a season-high 12 points and had eight rebounds, while freshman Maite Cazorla had seven points and seven assists. Lexi Bando and Lexi Petersen each contributed nine points for the Ducks, who return to action on Monday at USC (5 p.m., Pac-12 Networks).

“I thought that we were put on our heels early in the game, until we adjusted to the pressure. Then I thought we were just fine,” head coach Kelly Graves said in an interview with Oregon IMG Sports Network after the game. “When you get that pressure for the entire game, it can kind of ware you out. And it did us.”

The Ducks lost the rebounding battle (45-35) and were 44 percent from the field, compared to UCLA’s 42 percent. UO shot 27 percent from 3-point range and UCLA shot 53 percent. Coming into the game, the Ducks were second in the NCAA in 3-point percentage with 43 percent.

Both teams combined for 33 turnovers.

UCLA led 23-15 after the first quarter, but a 9-2 run capped by a pair of Alleyne free throws gave the Ducks a 33-31 lead with 2:31 before halftime. The Ducks had their largest lead of five points (42-37) with 9:07 to go in the third quarter on a 3-pointer from Bando. After that, UCLA strung together a 16-5 run to lead 53-47. The Bruins led 63-51 after three quarters.

“Overall, I was encouraged,” Graves said on Oregon IMG. “We haven’t played the kind of schedule that has really tested us. This was our first huge test in terms of, they’re a top-25 team legitimately. I think we proved we can play.”

In the fourth quarter, the Ducks got to within eight points of the Bruins at 69-61 with 6:09 left in the game, but a free throw and a 3-pointer from UCLA’s Nirra Fields, who had 31 points, gave the Bruins a lead of 73-61.

“Tonight was actually good in that we’ve now seen a taste of that pressure that we’re going to see again on Monday night (at USC),” Graves said.

Follow Jonathan Hawthorne on Twitter @Jon_Hawthorne