Another outstanding bowling spell from English import Henry Barrow led Mooroopna to make a huge statement to the entire Haisman Shield competition.
A second five-wicket haul in three games for Barrow made defending champion Numurkah's top order crumble, and allowed the Cats to go fourth on the table with a 42-run win.
Chasing 153, Numurkah was quickly 5-33 after Barrow dismissed the entire Blues top five, including the prized scalps of Dylan Grandell, Josh Smith and Shaun Downie.
The steady hands of Michael Eckard and Blues skipper Liam Gledhill looked to steer the ship to safety, but the duo went for 29 and 22 respectively as Mooroopna wrestled control back.
Simon D'Elia picked up three wickets to help mop up the tail, with Numurkah rolled for 111 to give Mooroopna a confidence-boosting win.
After a slightly sub-par batting output of 153, Mooroopna captain Sam O'Brien was relieved his bowlers had stood up.
“We knew we had to bowl well obviously to win, but luckily Henry Barrow was absolutely super,” he said.
“He took 5-28 off his eight overs, it was an absolutely unbelievable individual performance, he bowled the ball in perfect areas. He definitely led the way, he was fantastic from ball one until the end of his spell.”
The Cats got 34 from Mark Kitto and 26 from Mat MaCansh to post the competitive total.
“It was a really good win, and a fantastic result for us. We had some really good performances throughout the game which made it possible,” O'Brien said.
“It certainly helps the morale of the group, but at the same time we still need to work hard for the rest of the season to keep striving for the top.
“We certainly are (enjoying our cricket), there's a good morale at the club. We'll keep working hard, and hopefully that brings results with it.”
The result was Numurkah's first loss since round seven of last season, having reeled off 13 straight wins that included the Haisman Shield grand final.
Mooroopna 153 (Mark Kitto 34, Mat MaCansh 26, Shaun Downie 4-17) defeated Numurkah 111 (Michael Eckard 29, Liam Gledhill 22, Henry Barrow 5-28)
Henry Barrow (Mooroopna): An exceptional spell of bowling from the import quick had him rattle off the first five wickets of the Numurkah chase, leaving the Blues 5-33. If he keeps this level of play up, the Cats can beat anyone this season.