The Cats have now leap-frogged the Murray Bombers into second on the A-grade standings courtesy of the strong 55-33 victory at Victoria Park.
A fast start to the Cats saw Echuca playing catch-up for most of the match, trailing by six goals at the first change.
Echuca retaliated with a 13-all second quarter but Mooroopna pulled away once again in the third to hold a 13-goal lead at the final change.
The Murray Bombers could only manage four goals to 15 amid a Mooroopna onslaught to concede their second defeat of the season.
Jacqueline James, Bianca Willis, and Greta Pearson fought hard for the hosts but the Mooroopna trio of Dayna Williams, Maddison Wong and Shelby Britten were all class in a crucial win for the Cats.
Looking ahead, Echuca has another tough assignment in round 10 when it travels to Deakin Reserve in what shapes as a blockbuster third-versus-fourth clash against Shepparton United.
Both perennial contenders over recent seasons, each side boasts a 7-2 record with the winner poised to leap clear of its rival.
United notched a 37-goal win over Tatura away from home in round nine, while around the courts Shepparton Bears pipped Kyabram in a thriller, 56-55.
Rochester gave ladder-leader Seymour a fright but the Lions’ class shone through to take a 12-goal win over the Tigerettes.
Shepparton Swans and Euroa were the other A-grade sides to claim wins in another exciting round of GVL action.