Ole Miss dropped a 10-5 decision at Arkansas State, while MSU lost 2-0 at home to Central Arkansas.
It was the first shutout loss for the Bulldogs at Dudy Noble Field since a 6-0 win by Samford in 2004.
Both teams must now quickly regroup for their final SEC games, as all league series begin on Thursday.
Ole Miss (34-19, 14-13 SEC) visits Vanderbilt, while Mississippi State (31-21, 13-14) will be home against No. 4 Kentucky.
While both the Rebels and Bulldogs are assured of playing in the SEC Tournament when it begins next week in Hoover, Ala., Tuesday's losses won't look good on the NCAA tourney resume at seeding time - Central Arkansas (23-26) had an RPI of 191 in the latest NCAA computations, while Arkansas State (29-21) was at 140.
A quick look at both games:
Ole Miss: The Rebels took a 2-0 lead when Zach Kirksey hit his 13th home run in the second inning, but six Ole Miss pitchers - including senior Jon Andy Scott of Booneville - were rocked for 14 hits by the Red Wolves.
"We gave ourselves no shot tonight on the mound," said Ole Miss head coach Mike Bianco. "We gave up a couple of big innings which is the kiss of death."
ASU, leading 3-2, scored five runs in the fifth to break the game open.
Mississippi State: The Bulldogs had enough pitching, as Wheeler freshman Brandon Woodruff (0-2) and four relievers combined on an eight-hitter. But MSU has managed just four runs in its last four games.
"Our kids did not meet the challenge," Bulldogs coach John Cohen said.
Woodruff allowed five hits and one run in four innings, with four strikeouts and two walks.
Leadoff hitter Adam Frazier went 3 for 3 for MSU.
Ethan McKenzie, making his first start for the visitors, scattered five hits over six innings.