STILLWATER, Okla. -- One play ignited Oklahoma State and sent Southeastern Louisiana sinking.

The No. 21-ranked Cowboys recovered a botched punt return for a touchdown -- on Southeastern Louisiana's first touch of the ball -- and romped to a 61-7 win in the season opener for both teams at Boone Pickens Stadium on Saturday.

The Lions, an FCS foe and such a decided underdog that no betting line was offered, figured to need a strong start to threaten an upset, or at least manage a competitive game into the fourth quarter.

The Lions produced a stop on the game's opening drive. Then return man Juwan Dickey tried to field Zach Sinor's punt at his own 4-yard line, failed to handle it, and Oklahoma State had the game's first score when freshman Madre Harper smothered the ball in the end zone on the first play of his college career.

"You always want to start these games fast," said Cowboys coach Mike Gundy. "We know we're a more talented team, everybody understands that. But you want to make sure you start fast. You don't want to get put to sleep. You don't want to be the one who turns the ball over and they hit you on a big play.

"You want to start the game the right way. And take control."

The Cowboys didn't punt again until the backups were in. They led 28-0 at the end of the first quarter and won a home opener for the 21st consecutive season.

Southeastern Louisiana lost for the 21st consecutive time to an FBS opponent.

Three plays after Harper's score, the Cowboys' defense set up another quick score when defensive end Cole Walterscheid stripped Lions quarterback D'Shaie Landor for a fumble that safety Tre Flowers recovered at the Southeastern Louisiana 36.

Running back Chris Carson capped a four-play drive with a 14-yard touchdown run and Oklahoma State's lead was 14-0 just 4:10 into the game.

"It was huge," Lions coach Ron Roberts said of the muffed punt. "We open up the game, get a stop, they punt it. Then we fumble the punt and they get a touchdown. Then on our first drive on offense, we fumble again and the floodgates opened. The crowd got into it and their players fed off it and they put a whooping on us."

Cowboys quarterback Mason Rudolph hit receiver Jhajuan Seales on a 24-yard scoring pass, before tailback Barry J. Sanders added a 1-yard rushing touchdown to boost the lead to 28-0 -- all before the end of the first quarter.

Southeastern Louisiana scored a first-half touchdown, although against mostly Cowboys reserves, on a 26-yard scamper by running back Kaelyn Henderson. That cut the lead to 31-7.

The Lions didn't score again, while Oklahoma State tacked on, mostly with reserves.

Overall, Southeastern Louisiana totaled 203 yards, while turning the ball over four times.

"We actually work on getting six turnovers every practice," said Oklahoma State cornerback Ramon Richards, who scored a defensive touchdown off a fumble return. "The defense, we played great. We can always improve. But great day today."

Lindor completed just 1 of 6 passes for 12 yards and ran for 3 in the Lions' option offense, before giving way to backup Justin Alo. Henderson ran for a game-high 68 yards.

"We thought we prepared well," said Southeastern Louisiana offensive coordinator Matt Barrett. "Obviously, we're playing a great football team and a tremendous, talented defensive front. Hats off to them."

Rudolph completed 18 of 26 passes for 188 yards and two touchdowns, while playing about half the game. Seales turned three catches into 61 yards and two scores.

NOTES: Barry J. Sanders didn't choose his legendary father's school out of high school, instead signing with Stanford to forge his own path. But with Christian McCaffrey entrenched at tailback for the Cardinal, Sanders headed to Oklahoma State as a graduate transfer and made an impact in his first game as a Cowboy. Sanders scored on a touchdown run, nearly scored on a 57-yard punt return to the 1 and added an 18-yard reception. ... Southeastern Louisiana disbanded its football program for a while, before restoring the sport in 2003 and operating at the FCS level. Since then, and including Saturday, the Lions have played 21 games against FBS schools. And lost all 21. The trip to Stillwater at least came with a payday, as Southeastern Louisiana collected $385,000 for the visit. ...Since 2010, Oklahoma State leads the nation in non-offensive touchdowns. The Cowboys added two more to their total, now 39, against Southeastern Louisiana.