A day of torrential rain in Western Sydney couldn't dampen the quality of football from both sides.
Masterful long kicking and epic defence from both teams came before and a couple of superb attacking plays decided the match.
Sivo's two aerial masterpieces, out-leaping opposite George Jennings from high attacking kicks, proved the difference.
Happy Eels coach Brad Arthur praised the kicking of halfback Mitchell Moses but cautioned his side now needed to continually replicate that performance.
"I know it was wet conditions but I thought both teams completed reasonably high, traded blows, it was end to end," he said.
"I think Mitch's kicking game was great. Sometimes we struggled to get out of our end with their pressure from their defence and Mitch came up with some great kicks, kicked us out of trouble a few times then on the back of it it it gave us a bit of energy and the boys chased hard.
"If we want to be the sort of team they are and challenge, we need to make sure we do that every week, it doesn't matter who we play. We need to have the attitude that's how we play."
The Eels lost centre Waqa Blake during the week to a calf strain with forward Marata Niukore, in his first game of the year returning from suspension, filling in with great effect.
Far from being caught out by the faster men opposite, Niukore used his size to repeatedly rock the men opposite, causing indecision and at least one turnover.
Skipper Clint Gutherson was also tremendous; both he and opposite Ryan Papenhuyzen put on a clinic of positional fullback play but it was Gutherson was the superior performance and last laugh as he helped save no fewer than four Storm tries.
The Eels scored first points as Sivo out-jumped former Eel Jennings from a pinpoint Dylan Brown bomb.
But with half-time looming, yet another Storm raid paid dividends.
After Gutherson knocked the ball away from Kenny Bromwich to prevent a try, the Storm regathered and spread it rapidly to the right for Reimis Smith to bag his first try in Storm colours to make it 6-6 at half time.
The game threatened to flare up when Felise Kaufusi's was placed on report in the 47th-minute after a tackle which forced Ryan Matterson from the field for a HIA. He would not return.
The torrential rain and monstrous collisions sapped players from both sides; Brandon Smith could barely stand when finally interchanged for rookie Tyson Smoothy in the 63rd minute.
Moses and Reed Mahoney's long kicks to the corners started to take their toll on the Storm back three and helped the home side to a better share of field position through much of a scoreless opening 20 minutes of the second half.
A leg-pull penalty and long touch-finder put the Eels in range and an offside six-again mounted the pressure, then some sharp dummy-half work from Mahoney helped Junior Paulo crash over for his second try in as many games to put the Eels up 12-6.
The Storm weren't done with as Justin Olam cashed in on a lucky ricochet from an attacking grubber with Papenhuyzen levelling the scores with five minutes to play.
With both side almost certainly thinking about a field goal, the Eels finished a set with a Moses bomb from more than 40 metres out but it floated high and long and a rampaging Sivo charged through to snatch it from Jennings for the second time in the match as the Eels stole the lead from nowhere.
But there was one more twist in the tail and a grandstand finish in wait.
Melbourne's short kick-off was touched by Eels centre Tom Opacic before it had the chance to travel 10 metres to give the Storm a penalty and a full attacking set with over a minute to play but an all-or-nothing play from Olam on the second play ceded possession and allowed the Eels to run down the clock for a well-earned upset win.