Logan Crowley of Southland scores a try at Rugby Park on Saturday. Photo: Getty Images
Having scored four first-half tries at Invercargill's Rugby Park, it looked as if Southland would finally claim a win after 26 straight losses.
But two quick tries after the break through unwanted All Black Ngani Laumape put Manawatu right back within striking distance.
A further try to Rhys Pedersen and conversion from Otere Black put Manawatu in front, and Black added a penalty before Manawatu hung on for a remarkably unconvincing victory.
Southland pick up two bonus points for their efforts - their first points of the season - but remain anchored to the bottom of the Championship ladder.
Manawatu sit in fifth.