Senior Allea Summers' goal in the first minute of the second overtime period gave the Lady Owls a 1-0 decision at Fulton, ending a 28-match league losing streak which dated to the middle of the 2010 season.
The Lady Hornets held a 10-3 advantage in shots on goal for the contest, with senior Lola Weiss and junior Jenny McCarty each getting off three attempts. However, they were all stopped by junior Ellen Woolsey, who recorded her first career shutout.
Summers had an earlier shot blocked by junior goalkeeper Billie Klutts, but her left-footed drive from 30 yards out in the second OT found the net for her team-high seventh goal of the season.
The loss prevented Fulton (8-12, 6-6 NCMC) from finishing tied for second in the conference race with Mexico. Moberly won its fifth straight title, the last four with perfect records, by five games.
Marshall (4-16, 1-11) is the fifth seed in the Class 2, District 9 Tournament at Moberly, which it begins Monday against Kirksville.