ANNAPOLIS, Md. -- As Houston quarterback Greg Ward Jr. walked to the locker room with his head down, a police officer at Navy-Marine Corps Memorial Stadium offered encouragement.

"Keep your head up," the officer told Ward, who kept walking without saying a word, staring at a loss Houston never saw coming after setting lofty goals to compete for a national championship.

Navy 46, Houston 40 is a reminder that it's really, really, really hard to go undefeated in college football. Perhaps Tom Herman, who speaks often about focusing on the conference championship, tested the football Gods this week on "The Dan Patrick Show" when he said unequivocally the Cougars could win the national championship in 2016.

"I think this year, certainly, yeah," Herman told Patrick. "I think we've got as good a team as anybody in the country for three hours on a Saturday."

For more than three hours Saturday, Navy played inspired for its first win over a top-10 team since 1984. Navy looked like the more focused, prepared and disciplined team, not Houston, which was missing two defensive starters because of off-the-field issues.

How big was this win for Navy? The superintendent announced that classes are cancelled Tuesday because of beating Houston. That's the first time that's happened since 2007, when Navy ended its long losing streak to Notre Dame.

How big was this loss for Houston? Stay tuned. That answer isn't clear yet. Herman got Houston to bounce back from a loss to Connecticut in 2015 for a 13-1 season and Peach Bowl win over Florida State.

The playoff hopes, though, are essentially over.

"It's hard to envision us getting the kind of consideration we want if we have one loss," American Athletic Conference commissioner Mike Aresco said before the game.

It's not difficult to imagine one day we'll look back at Oct. 8, 2016, as the start of a depressing trifecta for Houston: no College Football Playoff, no Big 12 invitation, and no Herman (once another school with more money comes calling).

"You know you're going to have one of these games every year and you hope you can survive it," Houston athletic director Hunter Yurachek said. "And we didn't."

This didn't feel like any loss. Houston players were in tears on the field after the game. Ward, a team captain, said he consoled some teammates in the locker room and several players had to console him.

"We're going to use this as motivation -- the hurt, the pain, to never feel this feeling again," Herman said. "This pain is awful. Losing is awful. But we've got to make sure they also understand we've got all of our goals ahead of us."

That's not entirely true. This team badly wanted to be in the playoff, even if players dodged the question Saturday. During preseason camp, Ward told his teammates at a team meeting, "As far as us [veterans] sitting in the front [row], we won a [conference] championship. We want a national championship. What are y'all going to do to help us, and what are we going to do to help y'all?"

Navy decided to force Ward to be a passer. He still ran for 94 yards and threw for 359 yards, but Navy devised a smart plan to take away easy throws.

"Most people don't want the ball in his hands but we thought they wouldn't want him running too much," Navy coach Ken Niumatalolo said. "He's their prized pupil and he's a phenomenal player. We just wanted to make it hard, to take away the easy bubbles and make them run."

College football dreams can change quickly. Within the span of one rainy afternoon before a half-filled stadium in Maryland, Houston went from CFP hopeful to needing Navy to lose two AAC games for the Cougars to even win their division.

There was Houston turning the ball over three times, including one interception returned for a touchdown. There was Houston snapping the ball out of the end zone for a late safety on a punt attempt. There was Navy rushing for 306 rushing yards against a Houston defense that entered the game allowing 42 yards per game.

"We've been practicing for the Houston defense all spring and at camp," Navy quarterback Will Worth said. "To be able to execute our game plan made the difference."

For the second time in two weeks, Houston's defense was without starting linebackers because of something off the field. Last week, middle linebacker Matthew Adams was benched after what Herman described as a "scuffle" between he and outside linebacker Tyus Bowser, who got hurt in the incident.

Bowser remained out of the lineup Saturday. Star linebacker Steven Taylor, one of the nation's sack leaders, missed the Navy contest with a one-game suspension for unspecified violations of team rules. Yurachek and Herman wouldn't say why Taylor was suspended.

Defensive end Cameron Malveaux, a team captain, brushed aside a question about whether he's bothered by losing key defensive players for off-the-field incidents in consecutive weeks. In reality, it's fair to wonder what these missing players say about Houston at the moment.

"I think anytime you lose a game you've got to look in the mirror as the head coach and ask yourself why," Herman said.

Losing is unusual for Herman. He's only lost three times in the past three seasons at Ohio State and Houston.

Sometime in the next couple months, it's very possible Herman will have multiple job offers, namely from major programs like LSU, Texas and/or USC. The reality is if at least one of those schools comes calling, it's hard to see Herman saying no. Coaches rarely turn down those types of jobs.

Herman understandably won't talk publicly about his job prospects during the season. Yurachek said he continually speaks with Herman and his agent, Trace Armstrong, about what's important for Herman as Houston's coach. Last year, Yurachek spoke with Armstrong for several months and got a raise for Herman and his assistants before the AAC championship game.

"Part of pushing our football program forward is for Tom Herman to be our football coach," Yurachek said. "I've got to make sure Tom Herman is still the head coach at the University of Houston. I don't think for him it's all about salary. Obviously, it's important. I think he wants to be able to compete for championships year in and year out, and I think that's by facilities, continuing to be able to raise our operational budget for our football program, and the ability to retain our great staff."

Houston's operational budget is about $2.8 million, not counting scholarships and salaries. Yurachek said he's eyeing the $4 million to $5 million range for Herman to keep moving forward at Houston.

Herman is so beloved in Houston that a Cougars fan created a GoFundMe account to raise money through T-shirts with Herman's face that reads, "Come And Take Him." So far, $20,000 of the $31,4000 goal has been raised.

"I don't know what their plans are to do with that, but maybe I'll get a check sometime soon from this group and we'll put it to good use for our football program," Yurachek said.

The season isn't over for Houston. But there's a reason going undefeated in college football is really hard.

Players get suspended. The star quarterback throws an ill-advised pick six. Human nature sets in to look ahead or feel the pressure.

Navy played inspired. The Cougars did not, and it burned them.