Kevin Parrom, of Arizona, holds up his hands to signal his hitting three three-pointers in a row during a game against Washington State at McKale Center. Wildcats won 73-56. Saturday February 23, 2013 Tucson, Arizona

Mamta Popat / Arizona Daily Star

There’s a reason why senior forward Kevin Parrom has started the Arizona Wildcats’ past three games, and it became obvious Saturday.

Just in time.

Parrom scored a season-high 19 points with 5-of-6 three point shooting, to cover up a host of deficiencies during the Wildcats’ 73-56 win over Washington State at McKale Center.

“As you can see, a senior late in February has a lot at stake,” UA coach Sean Miller said. “I don’t know where we would be in this game if Kevin didn’t play the way he played.”

Actually, he did.

“We wouldn’t have won without him,” Miller said later.

This much is certain: Parrom tied his career-high of five three-pointers, gaining confidence in a long-range stroke that had connected only 25.6 percent of the time in conference games, while UA stayed ahead most of the game by double digits.

They led by 16 at halftime, by up to 22 in the second half and were never seriously threatened the rest of the way while moving to 23-4 overall and 11-4 in the Pac-12.

But for a team that will head to Los Angeles this week for potentially difficult games at USC and UCLA, there were issues underneath it all that Miller could not see past.

The Wildcats allowed their opponent to shoot better than 50 percent in the second half for the third time in the past five games. Their offense regressed in the second half against the Cougars’ zone. They failed to secure several difficult rebounds against a desperate team that has now lost eight straight.

Bottom line: Arizona would have been in serious trouble had WSU not hit just 14 of 28 free throws.

Miller projected what that meant not only Saturday but also what it could mean for Wednesday’s game at USC.

“The final score was not indicative of our game because they missed an inordinate amount of free throws,” Miller said. “We were fortunate with that.

“But what happens is you move to the next game and everything’s OK, but it really isn’t OK, and you just get drilled at USC. It isn’t even close. You’re down 10 at the half and they just roll you right out of L.A. And it started not in the USC game but the Washington State game when we turned it off. It’s so hard to turn it back on effort wise when you turn it off.”

Curiously, the Wildcats had answered their defensive troubles against Utah (which hit 5 of 8 second-half three-pointers on Feb. 17), Colorado (50 percent field goal shooting in the second half on Feb. 14) and California (58.8 percent for the game on Feb. 10) by moving down Washington on Wednesday.

In their 70-52 win over the Huskies, the Wildcats allowed just 30.8 percent field-goal shooting while UW made just 1 of 11 three pointers.

That was all long forgotten by the second half Saturday, when the Cougars hit 52.2 percent of their shots after halftime.

“It’s terrible,” Miller said of UA’s second-half defense. “It’s terrible. That’s all I can say.

We’ve worked really hard. Practiced 80 times and … that’s not going to work. Guys gotta try. That’s disappointing.”

Miller didn’t have much better things to say about the second-half offense. While the Wildcats initially moved the ball well, recording 11 assists for 13 first-half baskets, they regressed in the second half.

Miller said part of the offensive trouble was carryover from the defensive side, with a lack of stops turning into a lack of easy baskets that can jump-start an offense. The other part was that, Miller said, some of the Wildcats were simply afraid to take shots against the Cougars’ zone defense.

“We’ve seen that in second half against Cal, where you can say, 'Hey, coach, your zone offense is terrible' and I would agree with you,” Miller said. “But if I took my dress shoes off and laced them up, I’d bet you I’d take a couple of shots from the left wing that would go in.

“So much of it is under pressure, game pressure, late in February, you gotta be able … to deliver.”

Parrom did. He hit two three-pointers in the first two minutes of the game to give UA an early lead it never gave up, then came back with three more in the second half even as the game grew tenser.

“We didn’t expect that,” WSU coach Ken Bone said. “The last time we played them, it was (Solomon) Hill with five or six.”

Hill actually packed in all six of his three pointers in the first half at WSU on Feb. 2, when UA won 79-65. That game also became a struggle for UA, with Brandon Ashley fouling out and Parrom being ejected when he hit the Cougars’ DaVonte Lacy.

But this time Parrom stuck around for 33 minutes and his best shooting performance of the conference season. He had struggled offensively in starts against Utah and Washington over the past week.

“I was patient these past few games, trying to get my shots down instead of forcing them,” Parrom said. “My teammates helped me out by getting me open for shots.”

Now if the Wildcats could just stop some shots on the other end, their future might look better.

“If you’re trying to win a regular-season championship and trying to win the Pac-12 Tournament,” Miller said, “trying to get the highest seed possible that in the NCAA tournament, and then enter that tournament knowing on a given day anyone’s capable of beating anyone else — we’re the team that won’t win. Because we pick and chose how hard we play on defense.”