"I had to take a deep breath on that one," Clark coach Scott Humphrey said afterward. "The main thing is that we were tough at the end. That's kind of been symbolic of our season. We always see adversity, whether it be once a week, twice a week or sometime during the game. These kids always find a way to fight through the adversity."
Knowles made 7-of-20 shots from the field, but connected when it mattered, especially in the second half.
"It probably wasn't one of his better shooting games, but sometimes you're going to have that," Humphrey said.
Humphrey added that Knowles didn't quit even though the shots were hard to come by at times.
"The thing about Preston is that he always finds a way to make the play," the Clark coach said. "He's not going to run from it. Some people fear the moment. He lives for it. He loves a stage like this and he made plays down the stretch."
Clark (26-7) advances to today's quarterfinals and will take on Louisville Ballard at 6:30 p.m. The Bruins defeated Owensboro 80-60 in the first of four games to conclude the opening round on Thursday.
The Cards held a seemingly comfortable 63-52 lead with 2:30 remaining, but Christian County's Jamaizz Baker connected on a 3-pointer with nine seconds remaining to tie the score at 68-68. The Colonels had a chance to win in at the end of regulation, but Baker misfired on another trey as time expired.
"It seemed like whoever had the ball last was going to make something happen," Christian County coach Kerry Stovall said. "We had the ball last, and had our opportunity in regulation and they took advantage of it into overtime."
Christian scored the opening bucket of overtime, but managed just one point the rest of the way as Clark regained the momentum.
Humphrey wasn't surprised by his opponent's rally.
"We had some missed free throws and I felt like we were getting a little tight there at times," he said. "We weren't sticking to our routine. I think you have to give Christian County a little credit. They have all the seniors and they've been there before. You're talking about kids who are 28-4, two-time regional champs and they're not just going to walk off this court without giving it everything they had.
"They made some plays and some threes, no question."
Clark made just one field goal in the extra period, but connected on 7-of-8 free throws in the final minute to seal the deal.
Humphrey praised the way his team overcame the Colonels' late rally and responded on a positive note.
"One thing we've built our program around is just being poised and composed," he said. "Good things happen, bad things happen. You've just got to find a way to fight through it.
"Our bad thing happened in the last two minutes of the game, but don't let that overshadow what we did for 30 minutes in regulation. I thought our kids really answered the bell today."
Christian 17 14 11 26 3 - 71
Clark 22 16 11 19 9 - 77
CHRISTIAN COUNTY (28-3) - Tandy 9, Baker 10, Dillard 3, Wilford 17, Trotter 8, M. Dillard 3, Wilson 2, Ivory 8, Ray 2, Manning 9.
CLARK (26-7) - Knowles 24, Hatton 12, Lewis 1, Rogers 4, Wood 5, Stenzel 9, Bennett 2, Jones 20.