The Giants had started the season 0-3, but booted the woeful Joe Slocum for another import point guard, Melbourne's Kyle Adnam.
While Adnam (13 points on 4/14 FG, six turnovers) had a rough debut against the defensive tenacity of Sharks guard Mitch Norton, he showed enough speed and creation to liven up the Nelson offence and create more open looks.
Alongside him, Dion Prewster had his best game of the season, dropping in 22 points and dishing seven assists as he sparked some off-the-dribble creation for the Giants.
That helped to keep the Giants in touch, with the Sharks' lead never progressing past 11, depsite some decent play from their core rotation.
Norton excelled throughout on both ends, finishing with 19 points, five rebounds and eight assists, while fellow starters Luke Aston (15 points), Reuben Te Rangi and Duane Bailey (12 points and five rebounds apiece) all produced solidly.
Sharks coach Judd Flavell managed to keep Finn Delany in check, sending double teams at him regularly. Thanks to Adnam and Prewster, Delany had a lighter offensive load than in the first three games of the season, but also had some foul trouble, ending with 10 points, seven rebounds, two assists, two steals and two blocks.
The Giants' coaching staff were possibly too passive with his foul trouble. Although they got some decent minutes from Ali Granger and Bronson Beri off the bench, it was probably asking too much for the second unit to sustain stretches where both Delany and Adnam sat, negating some of Nelson's newly found offensive spice.
One of those second unit members - Beri - hit two threes to keep them in the game in the fourth quarter, eventually sending the game to overtime.
With both teams tiring, Kay stood up. The Aussie big man took over in the clutch - helped by some crucial shots from Hayden Allen - feasting on the glass and at the line to finish with 24 points and 15 rebounds, eight of which were on the offensive glass.
Kay's contributions got the Sharks over the line, moving them to 2-1 on the season, with a tough, tiring, back-to-back looming against the Taranaki Mountain Airs, who would undoubtedly have appreciated the game going into overtime.
In tomorrow night's other game, the Canterbury Rams host the Supercity Rangers, with the game live streamed on nzherald.co.nz from 7.00pm.