HOUSTON — Moments earlier, they had scored swiftly and easily.

They trailed Texas Southern by seven points in the third quarter. They had the Tigers pinned on their own 1-yard line. They had momentum.

Then, almost as quickly, everything fell apart for Southern football team.

With a game-changing series that all but clinched a 29-15 victory on a cool, breezy Saturday night, Texas Southern changed everything.

In the finest game of his college career, TSU quarterback Riko Smalls capped a 10-play, 99-yard drive when he fired a 13-yard rope to receiver Joe Anderson, who made a sticky-fingered catch in the north end zone at rickety old Delmar Stadium.

Just like that, the Jaguars’ momentum was gone.

So, too, was their slim chance at finishing with a record above .500.

“We had some great opportunities,” SU coach Stump Mitchell said. “We (downed) some punts on the 3-yard line and the 1-yard line, and they still drove and scored. So that was more disappointing than anything.”

But for the hardy SU fans who made the trip west on Interstate 10, there was plenty of disappointment to go around.

Southern (3-6, 3-4) came into Saturday’s game looking for its first two-game winning streak in the Mitchell era. Having suffered four losses this season by fewer than six points, the Jaguars had rebounded to drop Alcorn State in last week’s home finale at A.W. Mumford Stadium.

They came to Delmar locked in a three-way tie for second place in the Western Division, a half-game behind Prairie View.

Texas Southern (4-5, 2-5) was coming off a disappointing 12-9 loss at Mississippi Valley State, in which the Delta Devils snapped an 18-game losing streak.

But instead of rolling over and calling it a season, the Tigers came out with energy and passion.

Meanwhile, the Jaguars’ up-and-down offense all but abandoned the run, gaining 12 yards on 14 carries against a stout run defense from TSU.

Led by freshman quarterback J.P. Douglas — who played from start to finish for the first time this season, leaving sophomore Dray Joseph on the bench — the Jaguars had their moments.

Late in a sloppy first half that included eight SU penalties—not to mention two drives inside the TSU 20-yard line that netted no points — the Jaguars pulled to within eight points, 15-7, when Douglas fired deep down the sideline to Jared Green for a 50-yard score.

Later, falling behind 22-7 in the third quarter, Virgil Williams’ long kickoff return set up a 24-yard throw from Douglas to Mike Berry, bringing the team to within seven points.

The Jaguars never scored again. In fact, in the fourth quarter, Southern failed to get a single first down.

“On offense, we just didn’t convert,” Green said. “That’s something we have to take care of.”

Minutes after Berry’s touchdown, Smalls led the Tigers on their crucial 10-play, 99-yard possession.

He was 6-for-6 on the drive and ran for 17 yards on a key scramble.

But Mitchell said the most frustrating moment came late on the drive. Southern stopped TSU on a third-and-8 at the SU 25-yard line, but officials flagged defensive tackle Brandon Turner for a late hit, giving the Tigers a first down.

One play later, Smalls hit Anderson in the end zone.

It was the second time Saturday that TSU finished a scoring drive that lasted more than 90 yards. The Tigers took an early 7-0 lead after a 95-yard possession in the first quarter.

Most of the 10,543 fans at Delmar Stadium expected to see Texas Southern, the reigning Southwestern Athletic Conference champion, stick with the formula it used for much of the past two years: play strong defense, stick with a brutal ground attack and wear out its opponent in the second half.

Instead, the Tigers stuck with a stunningly effective passing game. And, in doing so, they stuck Southern with another disappointing loss.

Smalls threw for a career-high 365 yards and three touchdowns, with no interceptions.

His three touchdown passes matched the total number of touchdown throws Southern had allowed in eight previous games this season.

Heading into the weekend, Smalls had completed 48 percent of his passes. Against Southern, he was 26-of-39 (67 percent). He ran for another 71 yards, and more often than not, when TSU needed a clutch play, Smalls made it, helping the Tigers convert two of three fourth downs.

“This game didn’t come out the way I expected it to come out. Not at all,” SU senior safety Demetric Rogers said. “This has to be the worst game, from the secondary’s standpoint, that we played all year.”

Smalls did his best to make it seem that way.