A late double from Mitch Jones gave Riverside Olympic hope before Glenorchy completed a 4-2 win at KGV.
The Knights dominated the first half, opening the scoring through Tyler Harrison in the sixth minute, adding a second from Nick Naden and only denied more by the agility of Olympic keeper Jarrod Hill.
When Rowan Heggie made it 3-0 eight minutes after the break and Knights struck the woodwork three times in quick succession, another Southern win between last season's two regional Championship winners looked a formality.
However, a tactical switch from Olympic coach Alex Gaetani turned the game on its head, Jones coming off the bench to pull one back on 74 minutes and volley in a stunning second in the 89th.
However, a minute into stoppage time a push on Declan Brown by Tom Prince earned the Riverside defender a second yellow card and handed the hosts a penalty which Brown converted.
He has kept us in so many games, like this oneRiverside coach Alex Gaetani on keeper Jarrod Hill
While heaping praise on his teenage keeper, Gaetani said his young side is still finding its feet and learning with every game.
"Our experience level is low which means each game they are experiencing situations they have never been in before, and that's a learning curve for everyone," he said.
"It's up to the playing group to find out what they need to do to flick the switch and turn it on.
"We know what we're capable of which is to expect to win against teams like this but we don't do it for long enough which says we are not quite there yet.
But we're getting there slowly."
Gaetani said Hill had been pivotal to his side staying in contests in their debut NPL campaign.
"He's been huge. In my opinion, in a different side he would be one of the best keepers in the league, if not the best. His shot stopping has been amazing and he has kept us in so many games, like this one.
"He is an extremely talented kid that I hope goes a lot further in the game and we are very lucky to have him."
Goals from Joel Stone and Max Fitzgerald gave leaders Devonport a 2-1 win in the top-of-the-table clash at Warrior Park where Joffrey Nkoso claimed Olympia's consolation.
Matt Sanders bagged four goals as Hobart Zebras beat cellar dwellers Clarence 6-1 in the late match at KGV.
South Hobart host Kingborough at Darcy Street at 2pm on Sunday.