The UCF Knights' defense collapsed in back-to-back games against ranked foes, and they face their biggest challenge on Saturday against the No. 2 BYU Cougars.

UCF allowed 48 second-half points, including 27 unanswered points against the No. 20 Houston Cougars and 21 straight against the No. 18 Oklahoma State Cowboys.

Late second-half failures closed the Knights' chances to upset. They led by 17 points against Houston in the third quarter and entered halftime tied at 21 points with Oklahoma State.

Defensive back Antione Jackson said the defense must step up and get crucial stops in big moments.

"We need to get a stop on fourth and two," Jackson said during Monday's press conference. "Or we need to get a three-and-out or a takeaway to help the offense out."

The Knights' defense often forced an early third-and-short or third-and-long, putting themselves in a favorable position to get the offense back on the field. However, their ranked foes are the best Big 12 teams in third-down conversions.

Houston leads the conference in third-down conversions at a 61.4% success rate. BYU is third-best at 56.5%, trailing Kansas State.

Jackson said the Cougars' Bear Bachmeier is a great quarterback, and the team has to prepare for his dual-threat ability. Bachmeier threw for 224 yards, one touchdown and one interception, and rushed for 45 yards and two touchdowns on 13 carries in an upset win over then-No. 2 Notre Dame.

The senior said BYU is a slower-paced team than Oklahoma State and wants to run exactly what they want to run. It could be an advantage for UCF, allowing the defense to get set and call out the offense's audibles.

Saturday's game is the toughest challenge the Knights will face since 2009. The Cougars dethroned the Fighting Irish for the No. 2 ranking and are the highest-ranked opponent to visit Acrisure Bounce House.

UCF's 35-3 loss to the Texas Longhorns at Darrell K Royal–Texas Memorial Stadium was the last time the program faced a No. 2-ranked opponent.

Defensive coordinator Alex Grinch wants to see an improved pass rush after finishing with back-to-back one-sack games before entering a bye week.

BYU is the third-worst passing offense, throwing for 179.8 yards per game, 1.6 yards more than UCF. It may be a sigh of relief for Grinch's pass rush, but the Cougars' offensive line has allowed three sacks this season, tying with Kansas State for first in the Big 12.

The Knights' second-half defense will be a significant factor in staying competitive against the highest-ranked program they've played at home.

Source: Yahoo Sports