For the past 24 games, the top-seeded Air Academy girls’ basketball team hasn’t met a challenge it couldn’t overcome - typically by 18 points or more.

But Tuesday, in an all-Pikes Peak region third-round clash against No. 17 Sierra, the Kadets’ perfect season was truly threatened for the first time.

Sierra, which last year had a Cinderella run to the state quarterfinals, led by as many as eight points in the third quarter. But Air Academy, led by a stand-out second-half performance by Kylee Blacksten, eliminated the deficit and fended off a Stallion comeback in a 48-44 victory.

“We were coming into win this,” said Sierra coach Joseph Williams. “We felt in our hearts that we could come in here and lace them up and go. We gave them our best shot but they’re No. 1 for a reason.”

With a two-point lead heading into halftime, Sierra came out fast in the third quarter, outscoring the Kadets 9-3 in the first four minutes, but a seven-point run put Air Academy back in the hunt.

“I feel like we started moving the ball more and doing our thing instead of trying to play their pace, and it started rolling,” Blacksten said. “I feel like I probably came out with some butterflies a little bit. We watched film on them but I wasn’t really sure of what to expect. It's the playoffs everything is on the line and everyone is going to play is hard as they can.”

Senior captain Liza Louthan drained a three with just seconds left in the third to take a 32-30 lead to the fourth.

A battle ensued from there as Sierra regained a short lead thanks to a 3-pointer by Jasmine Monroe-Shivers, but with two starters in foul trouble the Stallions had to back off its aggressive defense, allowing the Kadets to work the clock a bit in the fourth.

“We like to press, especially in the second half, but we couldn’t get that mojo because a lot of our key players were in foul trouble,” Williams said. “We’re an aggressive team when we press, but the way they were calling it I couldn’t afford it.”

Air Academy coach Phil Roiko said he saw a shift in momentum in the third quarter after the Kadets double-teamed Sierra leading scorer D’nae Wilson.

“We didn’t get a ton of baskets off of it but it changed our energy,” Roiko said. “I think we had more energy and (were) playing with some more passion and intensity so that helped us.”

Wilson tied the contest at 42 with a 3-pointer with two minutes to play, but Blacksten completed a three-point play to regain a lead which Air Academy would not relinquish. A pair of free throws by Zoe Sims and a free throw by Blacksten with 2.5 seconds left put the game on ice.

Air Academy’s 10-point run to close out the third quarter was a feat as the Kadets shot just 5-for-14 in the quarter. The team finished shooting 37 percent from the field and 18 percent from beyond the arc.

Roiko said he felt some similarities between Tuesday’s contest and Air Academy’s second-round game, in which the team went into the locker room tied with No. 32 George Washington before going off in the second half.

“We shot poorly in both games, but the difference was we were still playing really good defense,” Roiko said. “When we played George Washington (in the second round) but it was the defense that didn’t show up. Tonight even though we were down, the defense kept us in it.”

Blacksten led the Kadets with a game-high 16 points, 12 of which were scored in the second half. Sims followed with 14 and Liza Louthan had 12.

Sierra was led by Wilson who finished with 12 points. Azaria Lacour and Monroe-Shivers had nine each.

The Kadets move on to the state quarterfinals to face No. 8 Berthoud, which defeated No. 9 Mesa Ridge on Tuesday, 80-73.