GREENVILLE, N.C. _ As UCF broke its huddle on the sidelines, Darriel Mack Jr. trotted out onto the field at Dowdy-Ficklen Stadium.
The Knights' backup quarterback replaced Heisman hopeful McKenzie Milton in Saturday's starting lineup against East Carolina, catching many off guard.
Mack took the opening snap and plowed forward for a 12-yard gain on a delayed run.
UCF entered the game against the Pirates riding the nation's longest win streak spanning 19 games, but it was unclear whether the Knights would be able to extend that run without Milton.
Once again, No. 10 UCF (7-0, 4-0 AAC) would answer the challenge presented to them, this time earning a 37-10 victory over East Carolina and extending their streak to 20 wins.
Knights coach Josh Heupel said the decision to withhold Milton from the game was made after pregame warmups in consultation with the team's medical staff.
Heupel said the decision was health-related but he wouldn't go into specifics on the type of injury.
When asked whether or not Milton could have seen action if needed, Heupel said, "I'm done talking about that."
Milton was banged up during the Knights' 31-30 win over Memphis last week, leaving the field briefly in the fourth quarter but returning to finish the game against the Tigers. Milton told reporters Monday he tweaked his ankle after being flipped on his game-winning seven-yard touchdown run.
"My ankle kind of hurt more than anything for some odd reason, but you know I think adrenaline at the moment then that I really didn't feel anything," Milton explained when asked about the run.
Josh Heupel said during an ESPN2 interview Milton's absence was "a game-time decision. Didn't feel like he was ready to go."
The last time Milton didn't start a game for the Knights was Oct. 1, 2016, against East Carolina. The junior saw his 27 consecutive-starts streak snapped.
Mack struggled early on as he worked to get acclimated to running the offense. UCF was forced to punt on its first two possessions.
East Carolina, meanwhile, was working with a quarterback in Holton Ahlers making his first college start. The Greenville, N.C., native was impressive early on, guiding the Pirates (2-5, 0-4 AAC) to a 3-0 lead over the Knights midway through the first half.
UCF then put together its best drive of the game, starting at its own 15-yard line.
The Knights used an array of short passes and runs by Mack and Greg McRae as well as a key pass-interference penalty against East Carolina to drive down to the Pirates' 36-yard line. After failing to convert on third down, Heupel went for it on fourth-and-five.
Mack found senior tight end Michael Colubiale on an out route for a six-yard gain and a first down that extended the drive at the ECU 27-yard line. A fumble on a handoff by Mack forced UCF to settle for a game-tying 39-yard field goal by Matthew Wright.
On ECU's next possession, Ahlers was picked off by Nevelle Clarke at the UCF 48-yard line. It was Clarke's first interception of the season.
UCF drove to the Pirates' 24-yard line and Wright hit a 41-yard field goal to give the Knights 6-3 lead.
UCF went with some razzle-dazzle on its next possession, with Mack finding backup Quadry Jones on a screen lateral pass. Jones took a step back before lofting a pass to a streaking Adrian Killins for a 42-yard touchdown. It pushed the lead to 13-3 with 8:33 left in the first half and shifted momentum in the Knights' favor.
Mack settled down midway through the second quarter, directing a 10-play drive capped by a seven-yard quarterback keeper for a touchdown that gave UCF a 20-3 lead going into halftime.
ECU cut the lead to 20-10 midway through the third quarter after Ahlers found Trevon Brown for a 29-yard touchdown.
On its next possession, UCF took advantage of a pass-interference call to drive into Pirates territory. The Knights' offense stalled and the team settled for another Wright field goal. The 46-yard kick extended the UCF lead to 23-10 with 2:49 left in the third. It was Wright's longest field goal of the season.
ECU looked to have something going after taking over at its own 1-yard line. The Pirates drove 95 yards down to the UCF 2-yard line, but Ahlers fumbled the football on a failed jump pass and it was picked up by linebacker Nate Evans, who returned it 94 yards for the score.
UCF added another fumble recovery on the ensuing Pirates drive.
The Knights' defense delivered a big game to help offset Milton's absence, generating five turnovers.
With the Pirates deflated, McRae pounced.
He tacked on a 74-yard touchdown run to push the lead to 37-10 with 6:14 remaining.
Mack nearly pulled off another long scoring run, but it was called back due to a penalty.
The Knights now have a bye, giving Milton and Mack time to recover from bruising hits both quarterbacks have taken during the Knights' perfect run so far this season.
