Conference realignment ended more than a few annual rivalries, but there's a couple new ones that have become among the most entertaining in all of college football. For Houston and Memphis, it's a renewal of a rivalry that dates back across decades and multiple conferences. The two teams have played nothing but close games with crazy finishes since lining up as members of the American Athletic Conference in 2013, and Thursday night's showdown in Houston was no different. 

Houston held a 17-0 lead at halftime and had Riley Ferguson and the No. 24 Memphis offense beat. Cougars running back Duke Catalon was a little banged up going into the locker room (he would later return to the game and finish with three touchdowns) but things looked good for the home team at halftime. Even a triple-ice of the Memphis kicker worked. 

But after halftime, everything changed. Memphis' offense caught fire as Houston committed turnovers, and suddenly, a 42-point run propelled the Tigers to a 42-38 win. Here's how things turned so ugly for Houston in the second half.

1. It started on special teams: Houston, as a program, has fielded strong special teams play since joining the AAC. Houston followed Memphis' first touchdown with a clock-milking TD drive of their own. It was the perfect response to the Tigers' score, and then they gave up arguably the play of the game as Tony Pollard ran Memphis back into the game with this 93-yard kickoff return touchdown. It was Pollard's fifth kickoff return touchdown of his career and made the score 24-14 with 5:57 left in the third quarter.

2. Then Riley Ferguson caught fire: Memphis scored nearly every time it got the ball in the second half. It came down to third-down execution, and most of the touchdowns went to running back Patrick Taylor (four scores in a career performance for him), but Memphis moved the ball with quarterback Riley Ferguson. Anthony Miller finished with 178 yards on 10 catches, and Tony Pollard had 91 yards on nine grabs, leading a Memphis group of receivers that picked Houston apart 20 yards at a time. Ferguson finished the game with 471 yards on 33-for-53 passing with his only touchdown being the game-winning score to Sean Dykes on a 21-yard pass with 1:28 left to play. 

3. Houston had the worst errors at the worst time on offense: There was a strip-sack, another fumble and -- as Houston was mounting one last drive for the win -- an interception. Houston's offense put up more points than it did in the first half and mounted three touchdown drives that chewed up clock while putting points on the board. If it weren't for the three turnovers, Houston wins this game and is still alive in the American Athletic Conference race. 

Instead, Houston falls to 2-2 in league play while Memphis, already with a win against Navy, takes a big step forward in the AAC West standings moving to 3-1. The Tigers host Tulane next week in a Friday night game you can see on CBS Sports Network.