TUCSON, Ariz. (AP) - Brandon Ashley scored a career-high 21 points in his return to the lineup, and No. 2 Arizona shook off a shaky start to open the season with a 78-55 win over Mount St. Mary's Friday night.

Arizona was out of sorts early before closing the first half with a big run to build a 15-point lead that was barely challenged.

Ashley played confidently and moved freely, finishing 9 of 10 from the floor in his return from missing the final 16 games last season with a broken foot.

Rondae Hollis-Jefferson lifted the Wildcats out of their funk with harassing defense and an array of soaring dunks, finishing with 15 points.

An NCAA Tournament team a year ago, Mount St. Mary's managed to keep Arizona within reach for most of the first half. Once the bigger, more athletic Wildcats turned up the pressure, the Mountaineers couldn't keep up.

Kristijan Krajina led Mount St. Mary's with 13 points and Byron Ashe added 12.

The Wildcats entered the season with lofty expectations, even for a storied program like theirs.

Arizona returned five key players from a team that fell a few seconds short of the Final Four last season and coach Sean Miller added another stellar recruiting class, headed by Stanley Johnson.

But before the Wildcats could start their expected romp through the schedule, Miller issued a warning: The preseason hype may have been overhyped, at least for now.

Citing a lack of cohesiveness and depth, along with an ''identity crisis'' on defense, Miller said the Wildcats were nowhere near the airy preseason predictions.

Early on against Mount St. Mary's, it seemed to be onto something as Arizona looked a bit disjointed on offense, struggling with turnovers - five in the first six minutes - and getting good looks at the basket.

And, after needing 4 1-2 minutes to get its first field goal, Mount St. Mary's started hitting a few shots and was still within 28-25 late in the first half.

Then Arizona hit the accelerator.

Running off three straight steals and breakaway dunks in 45 seconds - Hollis-Jefferson's tomahawk was particularly nice - the Wildcats closed the first half with a 12-0 run to lead 40-25.

Mount St. Mary's had one more run in it, using a 6-0 spurt to pull within seven.

Arizona erased that hope quickly, using a 12-0 run to push the lead to 63-44 before cruising to the victory.

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TIP-INS

Mount St. Mary's: Mountaineers coach Jamion Christian grabbed guard Junior Robinson around the waist and carried him off the court at halftime after the frustrated point guard had three straight turnovers (six total) to end the first half. ... Mount St. Mary's missed its first six shots.

Arizona: The Wildcats played their first game at McKale Center after a $30 million renovation during the offseason. ... Johnson scored the first basket of his college career on a left-handed layup in traffic. He finished with eight points on 2-of-8 shooting.

UP NEXT

Arizona hosts Cal-State Northridge on Sunday.

Mount St. Mary's hosts Maryland-Eastern Shore next Wednesday.