HATTIESBURG — Southern Miss freshman right-hander Walker Powell admitted to a case of nerves Sunday prior to making the first start of his collegiate career.

But with the Golden Eagles scrambling a bit to find answers for a starting rotation struck by late-season injury and ineffectiveness, Powell turned in a more-than-good enough performance.

Southern Miss blew open a tight game with a seven-run seventh inning and wrapped up a Conference USA series sweep of Western Kentucky with a 13-4 victory at Pete Taylor Park.

The win kept Southern Miss (34-14, 18-6 C-USA) tied atop the conference standings with Rice (31-14, 18-6). Florida Atlantic (33-13, 17-7) is one game back of C-USA’s co-leaders, with Marshall (27-17, 16-8) two games behind.

With their fourth C-USA sweep of the spring, the Golden Eagles improved to 22-3 overall at Pete Taylor Park and are 12-0 in series finales this season.

“It’s hard to sweep in college baseball, in Division I,” Southern Miss coach Scott Berry said. “I don’t care where you are or who you are, it’s tough. But our guys have been resilient. Our pitching’s been a little wounded, so hats off to our bullpen and what they were able to do.”

With starter Cord Cockrell limited to two batters Friday because of shoulder issues and former Saturday starter Nick Johnson bumped to the bullpen, Powell gave the Golden Eagles 4 2/3 innings of effective baseball Sunday. He allowed four runs (three earned) on six hits, walked one and struck out two.

“I felt good in the bullpen before the game and I just wanted to go out there and do the best that I could,” Powell said. “It was my first start and I just wanted to go out there and do the best I could. I hadn’t thrown more than two or three innings in relief, so I wanted to do the best I could and let the offense get rolling.”

Relievers Luke Lowery (4-0), Hayden Roberts, Nate Johnson and Clay Tageant followed Powell and held Western Kentucky to three hits over 4 1/3 scoreless innings.

Southern Miss scored 12 of its runs in two innings, posting a five-run second inning to go with its seventh-inning splurge.

“The hitting got hot,” said Southern Miss center fielder Jake Sandlin, who was 2-for-5 with a double, three RBIs and two runs scored. “There were lots of zeroes, but we had some really big innings, so that’s always good. However you score them, it doesn’t matter if you score them.”

Western Kentucky (24-24, 10-14) took its first lead of the weekend by scoring twice in the second inning. With two outs, designated hitter Kaleb Duckworth doubled and scored on catcher Hunter Wood’s single to center.

When left fielder Leiff Clarkson attempted to bunt his way on board, Powell threw the ball up the right-field line, allowing Wood to score.

That lead didn’t last long, as some misadventures in the Hilltoppers’ outfield aided a five-run rally by the Golden Eagles.

Southern Miss left fielder Hunter Slater led off the bottom of the second against WKU left-hander Ryan Thurston (3-4) by dropping a flyball single into left, and he moved to second on a groundout by catcher Chuckie Robinson.

After Thurston walked Tracy Hadley and Nick Dawson to load the bases, Dylan Burdeaux hit a liner into left that a diving Clarkson just missed, scoring Slater and Hadley. When center fielder Zach Janes bobbled the ball backing up the play, both Dawson and Burdeaux moved up a base.

Sandlin followed with a towering fly down the left-field line that Clarkson lost in the sun, allowing the ball to fall for a two-run double.

First baseman Tim Lynch followed with a big hopper that WKU first baseman Harrison Scanlon threw away, allowing Sandlin to score for a 5-2 lead.

Steven Kraft homered in the fourth inning and Scanlon had an RBI single in the fifth as WKU cut it to 5-4.

Southern Miss designated hitter Daniel Keating pushed the lead back to two runs when he led off the bottom of the fifth with his fourth home run of the season.

The Golden Eagles polished off the Hilltoppers by tying their largest single-inning outburst of the season. They sent 12 men to the plate and scored seven runs in the seventh.

Robinson collected his 10th and 11th RBIs of the series with a two-run single.

Dawson hit an RBI double in the big inning, while Sandlin and Lynch each had run-scoring singles. Second baseman Chase Scott drove in a run with a bases-loaded walk, and Keating pushed another run across when he was hit by a pitch with the bases loaded.

Slater and Lynch each finished with three hits, as Southern Miss bruised six WKU pitchers for 16 hits. Sandlin, Dawson and Scott each had two hits.