RAND-Walbundrie-Walla put last weekend's heart-breaking loss behind them to upset premiership contender Osborne by 21 points at Osborne on Saturday.
With coach Myles Aalbers setting up the win with three first-quarter goals, the Giants led at every change to claw their way back into the top-six.
It was the second year in a row Rand-Walbundrie-Walla has beaten Osborne at Osborne.
Jack Duck was outstanding in the ruck against taller opponents while his cousins Chris and Jeremy Duck were dominant at ground level.
The Giants stretched their lead out to 29 points in the third term before Osborne hit back to cut the margin to 13 midway through the final quarter.
But, unlike last weekend when they succumbed to late pressure from Culcairn, the visitors were equal to the challenge and steadied late.
"Our pressure was really good all day," Aalbers said.
"We were disappointed to lose to Culcairn the previous week after leading for most of the day and full credit to the boys for the way they approached Osborne.
"I didn't think we had a weak link.
"We needed to take a big scalp because there isn't a lot between most sides in the competition this year."
Osborne coach Matt Rava tried valiantly to lift his charges, Izaac McDonnell showed plenty of aggression in the midfield and George Alexander showed signs of returning to his 2017 form with some strong marking and four goals.
Lockhart consolidated its spot in the top-six by defeating Henty by 33 points at Henty.
With the Demons going into the clash without top-liners Jordan Harrington and James Creasy due to injury, Abe Wooden, Sean Wilkinson, Andrew Emery and Neil Irwin stepped up superbly to grab the club's fifth win of the season.
Harrington could miss at least a month with a groin injury.
Henty led by 10 points at half-time with Damian Cupido and Taylor Clark playing well before the midfield supply dried up.
Cupido kicked seven majors despite close attention from Jake Phillips.
The Swampies were again missing Daniel and Dale Cox, Jared Brennan, Kim Kantilla and Will Farrer.
Culcairn star Jye Shields did his Azzi medal chances no harm by starring in the Lions' 32-point win over Howlong.