There was even a hashtag created on Twitter calling for Casteel to be fired.
It's funny how quickly those sentiments changed after another half of football.
"They did a really good job of coming back when it was cold and 10 points down. They could've folded, but they fought back," Casteel said. "That's a feather in their cap, and something that they can hopefully build off of."
In the second half of that game, WVU didn't allow a point. Instead, the Mountaineers forced three turnovers led by two interceptions by cornerback Brodrick Jenkins, and put RU quarterback Gary Nova in tougher situations with pressure and coverage improvements.
"We didn't change anything. We just started to make plays, and that's something that they didn't do in the first half," Casteel said. "We didn't knock people down and knock people back. If you get knocked around and don't take advantage of opportunities, you play like we did in the first half."
If you want a turning point to look back on, take it from Jenkins, who said that halftime was something special. Reserve cornerback Brantwon Bowser spoke from the heart in the locker room.
"He was talking about playing for each other instead of just trying to play for the coaches," Jenkins said. "We need to put more enthusiasm into what we're doing and not just be out there talking."
"It really opened to some of us … I feel as if he's an older brother to me, so I really did take (what Bowser said) into consideration."
It seemed, despite the lackadaisical play from the defense in the first half that the players weren't worried.
WVU let its play defensively take the trash out in the second half, though.
"It was cold, and it was playing a lot of mind games on us. In the second half, we decided that we couldn't come back to WV with a loss, so we just dug deep and came back," Irvin said.
The question still remains, however: How does the same defense play one awful half of football and another stunning one in the span of four hours?
"Honestly I don't know. I wish I knew," said senior cornerback Keith Tandy. "When we have fun and the guys are flying around, we are good … But we've got to keep their heads up. That's the main thing."
It's something that has to continue this weekend vs. Louisville if the Mountaineers' defense wants to be considered consistent.
Prior to the second half of the Rutgers game, the only thing that fans were saying about the unit was that they were consistently bad.
Proving consistent against a dual-threat quarterback will be difficult, as the Cardinals' freshman Teddy Bridgewater is one of a kind.
"It can't be like last weekend when we'd get close to the quarterback, because he will get out of it," said linebacker Doug Rigg. "It's just a matter of rattling him and trying to get some pressure on him."