The Tigers (9-6) broke open a 1-1 game in the fifth inning by sending 14 batters to the plate. Quinn Stewart put LSU ahead with a two-run homer, his team best fourth of the season.
LSU then got consecutive singles from Aaron Hill, Ryan Patterson, Ivan Naccarata and a two-RBI base hit from Clay Harris for a 5-1 LSU lead. Blake Gill, Dustin Weaver and Bruce Sprowl followed with RBI singles to make the score 7-1.
Winthrop's third pitcher of the inning, Danny Bean, finally recorded the first two outs of the fifth, but Hill came back for seconds with another base hit to push in the eight LSU run.
It was the biggest run total in a single inning for LSU since scoring eight last season in the sixth inning of its second game with Houston.
The Tigers totaled 17 hits for the night, with Weaver leading the way with a 3-for-4 performance. It was his first multi-hit game for the Tigers.
Gill provided the tenth run of the game for LSU with his first home run of the season, a solo shot in the eighth inning.
Brian Wilson (3-2) picked up the win for LSU, lasting five innings and giving up one run on six hits with a season high six strikeouts and one walk.
LSU relievers Nate Bumstead replaced Wilson and retired six straight batters, and Jordan Faircloth took over to start the eighth and sat three more Eagles before giving Jacob Dempsey led off with a home run in the ninth.
LSU faces Winthrop (9-4) in the second game of their series Saturday at 3:30 p.m. The game time was pushed back 90 minutes to allow LSU fans to attend men's basketball game against Alabama at 1 p.m.