LSU (26-9, 10-5 SEC) won its ninth consecutive SEC series, dating back to last season. The Tigers are one-half game behind first-place Arkansas (10-4) in the SEC Western Division.
LSU trails Georgia (11-4) by one game in the overall league standings.
Alabama fell to 22-12 overall, 7-8 in SEC play with Sunday’s loss. Alabama had won 10 consecutive SEC home series prior to dropping two of three games to LSU.
“I’m very proud of our players for winning two games against an outstanding Alabama club,” said LSU coach Paul Mainieri. “Alabama can really swing the bats, but we showed today that we can have a productive offense as well.”
LSU produced a season-high 19 hits, including two doubles, one triple and two homers. Dean was 3-for-4 on the day with one homer, one double and five RBI.
Dean, who had just two homers on the year entering the series, launched two homers and collected 10 RBI in the three games.
Senior right-hander Louis Coleman (8-1) worked six innings to earn the victory, limiting the Tide to three runs on five hits with four walks and six strikeouts.
Alabama starter Adam Scott (1-1) was charged with the loss, as he surrendered five runs on eight hits in 4.1 innings with no walks and three strikeouts.
Second baseman Ryan Schimpf launched a solo homer in the top of the first inning to give LSU a 1-0 advantage.
The Tigers expanded the lead to 2-0 in the second on an RBI single by rightfielder Mikie Mahtook.
Alabama responded with two runs in the bottom of the second as third baseman Jake Smith unloaded a solo homer and catcher Vin DiFazio produced a run-scoring double.
LSU regained the lead in the third on an RBI single by Dean, but Alabama tied the game at 3-3 on a solo homer by rightfielder Kent Matthes, his 20th dinger of the season.
Dean’s two-run double in the fifth off reliever Adam Morgan gave LSU a 5-3 lead, and the Tigers expanded the margin to 7-3 in the sixth as Mahtook delivered an RBI triple and third baseman Tyler Hanover produced a run-scoring single.
Dean led off the seventh with a homer, his second of the series and fourth of the year.
“We knew entering the weekend that this could be our biggest challenge of the season, and I’m extremely pleased with the way our players responded,” Mainieri said. “We needed a big day at the plate, because no lead is safe against this Alabama team.”
The Tigers added four more in the eighth as Schimpf, shortstop DJ LeMahieu and centerfielder Leon Landry each contributed RBI singles, and Dean lifted a sacrifice fly.
Alabama scored an unearned run in the eighth off reliever Matty Ott, and the Tide launched three solo homers against Ott in the ninth. Daniel Bradshaw, however, retired the final two Crimson Tide batters to preserve the win for Coleman.
LSU opens a six-game homestand Tuesday when the Tigers play host to UNO in Alex Box Stadium.