STARKVILLE — Leftfielder Leon Landry launched three homers and collected seven RBI Saturday to lead second-ranked LSU to a 15-4 win over Mississippi State at Dudy Noble Field.

LSU (41-15, 20-10 SEC) clinched a share of the 2009 Southeastern Conference regular-season title, and the Tigers will be the No. 1 seed in the conference tournament, which begins Wednesday in Hoover, Ala.

Ole Miss also finished the regular season with a 20-10 conference mark, giving the Rebels a piece of the league crown. LSU is the No. 1 seed in the league tournament by virtue of its series victory over Ole Miss on March 27-29.

Mississippi State completed its season with a 25-29 overall mark, 9-20 in conference play.

“I’m so proud of our players for winning the Southeastern Conference championship,” LSU coach Paul Mainieri said. “It’s a tremendous accomplishment to be champions of the best league in the nation. Our players come to LSU for opportunities like this, and it’s a tribute to their hard work and dedication that they’ve earned the right to be called SEC Champions.”

The league title is LSU’s first since 2003 and the 14th in school history, tying Alabama for the most championships in league annals.

LSU won 20 SEC games for the first time since 2003.

Landry enjoyed a phenomenal day at the plate Saturday, going 5-for-6 with three homers, seven RBI and three runs. His five hits and three dingers tied LSU single-game records.

Landry became the first LSU player to hit three homers in a game since Quinn Stewart in 2006.

Landry gave LSU a 1-0 lead in the first inning with a solo homer, his first dinger since March 22 at South Carolina.

LSU erupted for five runs in the second as first baseman Ryan Schimpf lined a two-run double and designated hitter Blake Dean launched a three-run homer, giving the Tigers a 6-0 advantage.

The Tigers increased their lead to 7-1 in the third on Landry’s RBI single before the Bulldogs narrowed the gap to 7-2 in the bottom of the frame on an RBI double by first baseman Connor Powers.

LSU scored three runs in the fifth when Landry belted a two-run homer and Dean lined an RBI double.

Mississippi State responded with two runs in the bottom of the fifth as rightfielder Ryan Collins delivered an RBI double and designated hitter Ryan Duffy lifted a sacrifice fly.

LSU added five runs in the eighth as rightfielder Jared Mitchell ripped an RBI triple, and second baseman DJ LeMahieu plated Mitchell with a sacrifice fly. Landry capped off the inning with a three-run blast to give the Tigers a 15-4 lead.

Senior right-hander Nolan Cain (4-0), who entered the game in relief of Austin Ross after the rain delay was credited with the win, as he allowed three runs on five hits in three innings.

LSU also received an outstanding relief effort from right-hander Daniel Bradshaw, who worked a perfect three innings from the sixth through the eighth, recording two strikeouts.

Mississippi State starter Devin Jones (0-4) was charged with the loss, as he surrendered six runs on seven hits in two innings with two walks and one strikeout.