Johnson scored a game-high 24 points for Arizona (15-0, 2-0 Pac-12), which was coming off one of the most impressive defensive performances in program history. The nation's top team beat Washington State 60-25 on Thursday, shattering the McKale Center record for least points given up in the process.
"Nick is a veteran and very talented player," praised Arizona head coach Sean Miller. "We've seen him put it all together here this year."
Aaron Gordon donated 18 points and 11 rebounds to help Arizona take sole possession of the second best start in program history.
"At halftime I only had one rebound and I was mad about that," said Gordon. "Going into the second half my mindset changed and I just need to have that going into games."
C.J. Wilcox netted 20 points in the setback. Perris Blackwell added 12 points and 12 rebounds as the Huskies (9-6, 1-1) saw their three-game winning streak come to an end.
Nigel Williams-Goss' jumper late in the first period snapped a 33-all tie and gave the Huskies momentum heading into the locker room.
Washington's biggest lead of the game came just over three minutes into the second half, when Williams-Goss finished a three-point play for a 42-36 margin.
The Wildcats kept it close and eventually pulled in front for good on a Gordon jam at 9:54.
It was 60-58 in favor of the hosts when Johnson took a handoff at the top of the key, turned the corner and exploded for an above-the-rim finish. Moments later, Johnson drove and missed a pair of layups, but Gordon was there for a tip-in to restore a six-point lead for Arizona.
Johnson and T.J. McConnell combined to sink 6-of-6 free throws down the stretch to secure the victory.
Earlier, Shawn Kemp, Jr. came off the bench and provided a spark for the Huskies, scoring all nine of his points in the opening 20 minutes. Washington shot 15-of-27 as a team in the period and led 35-33 at halftime.
Arizona outscored Washington 42-30 in the paint and 10-0 in transition ... The Wildcats improved to 67-11 under Sean Miller at home ... Arizona has now won the rebounding margin in all 15 games this season ... McConnell had six assists and four steals.