MEMPHIS, Tenn. (AP) -- Jeff Kelly threw two touchdown passes, Derrick Nix rushed for 139 yards, and Southern Mississippi's defense did the rest.

Kelly threw a 25-yard TD pass to Josh Gulley and a 57-yard scoring strike to Todd Pinkston in the first half as No. 25 Southern Miss beat Memphis 20-5 Saturday.

"We had a great first half throwing the ball," said Southern Miss coach Jeff Bower. "We challenged our offense in the second half to run the football better, and they met the challenge.

"I thought we really controlled the football in the second half, and that's what you have to do."

The Golden Eagles (6-3, 5-0 Conference USA) also relied on a strong defense that kept the Tigers (3-6, 2-2) out of the end zone and held Memphis to 227 yards of offense, including only 64 on the ground.

The victory assured the Golden Eagles of at least a share of the conference championship, the third time they've either tied or won the title in the conference's four-year history.

"They whipped us," said Memphis coach Rip Scherer, who was given a two-year contract extension last week. "They made the plays they had to and that's all there is to it."

Southern Miss took a 14-2 halftime lead on Kelly's two TD passes.

Kelly's scoring toss to Gulley midway through the first quarter capped a four-play, 67-yard drive that started with a sack. Prior to the touchdown, Kelly hit Shawn Mills for 40 yards on third-and-8 to give the Golden Eagles the ball at the Memphis 25.

Kelly threw a TD pass in the second quarter to Pinkston, who caught the ball near the Memphis 40, shook off defender Marcus Smith and went down the left sideline for a 14-0 Golden Eagle lead.

Meanwhile, the Golden Eagles defense smothered Memphis. Of the Tigers' seven possessions in the first half, four were three-and-out and a fifth ended in an interception by Southern Mississippi's Terrance Parrish.

Memphis only managed 4 yards of offense in the second quarter, and the Tigers' deepest penetration of the half came in the first quarter when they reached the Golden Eagles 35. The Tigers faked a field goal attempt, and failed to make the first down, coming up a yard short.

Memphis' only score came with 3:15 left in the half. With the Golden Eagles backed up to their own 1, punter Jamie Purser had little room to get off the kick. Memphis defender Quincy Stephenson broke through the middle of the line and blocked the punt out of the end zone for a safety.

The second half scoring was left to the field goal kickers, with Southern Mississippi's Brant Hanna connecting on a 48-yarder in the third quarter and a 28-yarder with just over nine minutes remaining in the game.

Memphis kicker Ryan White converted a 27-yard field goal with 5:17 remaining in the third quarter.