SAN ANTONIO - The University of Southern Mississippi came into Saturday's football game at the University of Texas-San Antonio as the proud owner of Conference USA's stoutest defense.
As it turned out, the Golden Eagles proved no match for the league's worst rushing offense.
UTSA scored early and often as the Golden Eagles dropped its first conference game of the season, 55-32, Saturday at the Alamodome.
The Roadrunners (2-3, 1-1 C-USA), who snapped a three-game losing streak, used big plays to push around the league's top-rated defense, racking up 532 total yards, including a school-record 339 yards rushing.
USM (4-2, 2-1) surrendered its most yardage since giving up 590 yards to Washington in a 44-31 loss on Dec. 26, 2015, in the Heart of Dallas Bowl.
The 55 points were the most allowed since dropping a 63-17 decision to Marshall on Nov. 8, 2014.
USM quarterback Nick Mullens threw for 370 yards and three touchdowns, but lost a fumble after being sacked in the fourth quarter and threw a goal-line interception late in the game.
Mullens played the final 20 minutes of the game with his right thumb wrapped after being injured during a pass attempt in the third quarter.
Mullens threw a 17-yard touchdown to tight end Jay'Shawn Washington in the first quarter, found receiver D.J. Thompson for a 35-yard scoring pass in the second quarter and hit receiver Chase Whitehead for a 33-yard touchdown in the final quarter.
He also threw a 2-point conversion pass to tight end Julian Allen to get the Golden Eagles within 48-32 with 6:47 to play, but was picked off at the 1-yard line by linebacker Josiah Tauefa on USM's next possession.
Running back Ito Smith rushed for 94 yards and a touchdown on 18 carries. Smith added 22 yards on three catches, giving him 116 total yards. Smith has scored at least once in 11 consecutive games.
But it was the Roadrunners' ground game that doomed the Golden Eagles.
UTSA had come into the game, averaging a C-USA-worst, 96.2 rushing yards a game. But against the Golden Eagles, the Roadrunners had two backs top 120 yards each and combine for five of the team's six rushing touchdowns.
Jalen Rhodes rushed for 165 yards and three touchdowns on 14 carries, including an 80-yard touchdown run. Jarveon Williams collected 122 yards and two touchdowns on 15 carries, including a 92-yard scamper late in the game to set up the Roadrunners' final score.
Receiver Matt Guidry scored UTSA's other rushing touchdown on a 20-yard reverse.
Quarterback Dalton Sturm was asked to throw the ball only 12 times, but he completed 10, including two, big pass plays that sparked the Roadrunners' quick start.
On the third play of the game, Sturm found Kerry Thomas Jr. for a 71-yard touchdown pass and a 7-0 lead less than 90 seconds into the game.
After forcing a Southern Miss punt, Sturm went up top again, connecting with Josh Stewart for 77 yards down to the Golden Eagles' 3-yard line, setting up Williams' touchdown run on the next play.
Sturm threw for 193 yards, with 146 yards coming on those two plays.
After being pinned at its 12-yard line, Southern Miss was forced to punt again, setting UTSA up at its own 43. The Roadrunners needed just six plays to cover the distance, with Rhodes carrying three times for 29 yards, including a 4-yard touchdown that put UTSA ahead 21-0 less than midway through the first quarter.
Mullens' pass to Washington got USM on the board, but two personal foul penalties helped fuel a five-play, 82-yard drive that Williams capped with a 6-yard run for a 28-7 UTSA lead.
Smith's 1-yard run brought the Golden Eagles within 28-14 early in the second quarter, but two possessions later, Rhodes popped an 80-yard touchdown run to give the Roadrunners a 35-14 lead.
Mullens found Thompson with his scoring pass to bring the Golden Eagles within 35-21 with 3:24 left in the first half. It was the third consecutive game Thompson had caught a touchdown pass.
But Victor Falcon hit a 45-yard field goal on the final play of the first half to give UTSA a 38-21 halftime lead.
Parker Shaunfield remained perfect on field goal attempts, knocking through his 10th of the season from 28 yards to get USM within 38-24, but the Golden Eagles' would get no closer.
Guidry scored on the reverse for a 45-24 lead after three quarters, and the Roadrunners made it 48-24 on Falcon's 26-yard field goal after D'Nerius Antoine fumbled a punt at his 13-yard line.
Mullens' TD pass to Whitehead and 2-point conversion got USM back within 48-32, but his interception less than 3 minutes was followed by Williams' 92-yard backbreaker and a 3-yard TD run by Rhodes.
Thompson led USM with seven catches for 89 yards, Allenzae Staggers had six catches for 92 yards and Whitehead three catches for 63 yards.
The Golden Eagles will travel to Louisiana State for a 6:30 p.m. kickoff Saturday at Tiger Stadium.