Betts, who had been out for an undisclosed medical reason, didn't start but entered the game in the first quarter. She scored her first basket on a 6-footer off the glass in the second quarter and finished with six points, nine rebounds and four blocked shots in 27 minutes.
The Bruins had gone 2-2 without Betts, who is averaging 14.8 points and entered Friday with the nation's best field goal percentage at 68.3%.
UCLA still had a short bench Friday with Angela Dugalic and Lina Sontag playing in the women's Olympic qualifying tournament in Brazil this weekend. Dugalic is playing for Serbia and Sontag for Germany.
It's huge," coach Cori Close said of Betts' return. "Obviously even more huge because we're missing Lina and Angela who are with their national teams, and good luck to Germany and Serbia.
"I think more than that is her spirit. Everyone was talking about that in practice yesterday. It's not that she's just a really good player; it's her energy and spirit for the sake of the team, and that was really missed. We're thrilled to have her back."
Arizona was also without four players.
Kiki Rice scored 20 points for UCLA on 9-of-12 shooting from the field. She had 10 points in the first quarter, while Jaquez scored 10 points in the third quarter. Rice shot 75%, but UCLA's four other starters were a combined 4-of-24. Jaquez was 8-of-15 shooting off the bench.
"In the locker room we were all really excited for her, excited to have her back," Rice said of Betts' return, "and then we got out on the court when she checked in there was a big applause for her, and that's exactly how we felt. Obviously she's a huge part of this team and we missed her so much, so it's so great to have her back."
The Bruins, who are third in the country in offensive rebound percentage, had 18 offensive rebounds.
UCLA (18-4, 7-4 Pac-12) led 31-28 at halftime and 48-43 after three quarters and always seemed to have an answer for Arizona (12-11, 4-7).
"We were doing good taking advantage of what was given to us," Rice said. "I think we had really good ball movement and we recognized who the hot hand was and our defense was leading to offense. And a lot of that was getting those easy reads and lead to points."
The Bruins went on a 9-0 run in the third quarter to take a 40-32 lead. When Arizona pulled within three points at 52-49 in the fourth, the Bruins went on a 7-0 run to extend the lead to 59-49.
The Wildcats had 20 turnovers.
"Offensive rebounds and turnovers really hurt us," Arizona coach Adia Barnes said. "We had a lot of turnovers in the third quarter that led to transition baskets, and those are daggers."
ESPN's Alexa Philippou and The Associated Press contributed to this report.