Zampa stepped up with the West End Redbacks needing 33 from the final 18 balls to crush an explosive 35 from just 15 deliveries and steer SA to its second straight one-day win with just two balls to spare.
The 27-year-old slapped fearsome quick Billy Stanlake for a huge six, before scooping Michael Neser for six from the first ball of the last over.
That made it nine to win from five balls and Zampa wasted no time getting there, carving consecutive boundaries through cover and square-leg.
"I had to take some risks ... flat-batting big Billy is always a risk but I pulled it off today," Zampa said post-match.
The leg-spinner also claimed two wickets with the ball but it was in-form quick Wes Agar (5/69) who did the bulk of the damage early after SA won the toss and chose to bowl.
The Bulls were in strife after Agar's four-wicket opening spell claimed key trio Usman Khawaja (5), Joe Burns (0) and Matthew Renshaw (0).
Queensland’s Marnus Labuschagne rescued the Bulls from 4/24 with an impressive 135 alongside Jimmy Peirson (48) as the hosts reached 9/295 from their 50 overs.
The Redbacks looked on track with Alex Carey (79) cruising alongside Callum Ferguson (91), before Carey was run out and Ferguson departed with the required rate creeping higher.
Jake Lehmann (54*) fought valiantly with an important half-century with Zampa’s match-winning innings lifting SA to 3-2 in the competition standings with two matches to come before the tournament final.
The Redbacks play their first home match of the Marsh Sheffield Shield from 1 November at Adelaide Oval with their next one-day match against Western Australia later in the month at Adelaide’s Karen Rolton Oval.