ANNAPOLIS, Md. -- No. 6 Houston's attempt to make an unprecedented chase to the College Football Playoff ended with a stunning 46-40 loss to Navy on Saturday.

The Cougars looked like the best chance yet for a Group of Five school to reach the height of the postseason -- be it the playoff or the BCS Championship Game -- after having knocked off Florida State to end 2015 and Oklahoma to start 2016. But going undefeated is incredibly hard, and the Midshipmen played an inspired game on a rainy day before a half-empty home stadium.

Houston quarterback Greg Ward Jr. lost three critical turnovers. That helped Navy's methodical option offense, which didn't have a turnover behind QB Will Worth, a backup entering the season. Houston was the highest-ranked team to visit Navy-Marine Corps Memorial Stadium since 1984, when the Midshipmen shocked No. 2 South Carolina.

Ward threw a 17-yard touchdown to Chance Allen with 1:57 left, cutting Houston's deficit to 46-40. The Cougars' onside kick was recovered by Navy, which was coming off a 28-14 loss to Air Force.

Leading 41-33 with 6:54 left, Navy had a chance to put a dagger in Houston's chances with fourth-and- 1 at the Houston 15. Coach Ken Niumatalolo opted to go for it, but fullback Shawn White was stuffed by Cougars linebacker Matthew Adams short of the first down.

But Houston couldn't move the ball on its ensuing possession. The Cougars' playoff hopes sailed out of the end zone on a bad snap by Byron Sampson for a safety with 5:39 left.

Worth threw two touchdown passes and ran for more than 100 yards, sometimes running over a Houston defense that was missing three starters. The Midshipmen's deliberate option running game held the ball for lengthy stretches, frustrating the Cougars as they constantly stayed on the field. Houston entered ranked third nationally in scoring defense (11.2 points per game) and first in rushing defense (42 yards per game).

Houston trailed 41-27 entering the fourth quarter, the second-largest deficit in coach Tom Herman's two seasons. The Cougars faced fourth-and-4 at the Navy 9-yard line early in the fourth quarter, but Ward completed a 7-yard pass to D'Eriq King and Houston scored on the next play.

On the ensuing extra point, Navy's D.J. Palmore blocked the kick to keep its lead at eight. It was Navy's first blocked extra point in six years.

Tied at 20 at halftime, Navy forced two turnovers by Ward on the Cougars' first two possessions in the second half. Both resulted in touchdowns.

First, Ward was sacked and lost a fumble that Navy recovered at the Houston 41. Worth then threw a 17-yard touchdown to Darryl Bonner. On the next possession, Navy's Josiah Powell intercepted Ward for a 34-yard touchdown and a surprising 34-20 lead.

Houston played without four starters: standout linebacker Steven Taylor (suspension for violating unspecified team rules), running back Duke Catalon (concussion), cornerback/kick returner Brandon Wilson (lower leg injury) and linebacker Tyus Bowser (broken bone after fighting with a teammate).

Taylor entered the week tied for seventh nationally in sacks (5.5). Houston athletic director Hunter Yurachek said Taylor's suspension was for one game and declined to provide details.