Buoyed by their 52-0 rout of Castleford, Hull threatened to inflict a second consecutive home defeat on the leaders when they led 10-6 early in the second half but the Giants finished the stronger side to claim a sixth win from seven attempts.
Shaun Lunt, Aaron Murphy, Joe Wardle and Scott Grix were the try-scorers for the Giants, with Ben Galea and Ben Crooks crossing for Hull.
In the evening's other game Catalan Dragons continued their habit of coming from behind at home to Widnes to seal a convincing 46-14 win over the Vikings.
The visitors raced into an early 10-point lead as they scored through Patrick Ah Van and Dave Allen. Ah Van duly converted Allen's try as the Vikings looked great value for their early lead.
But Catalan hit back and claimed tries of their own from Thomas Bosc, Steve Menzies, Louis Anderson, Oliver Elima, Damien Blanch, William Barthau, Mathias Pala and Zeb Taia. Bosc also sent over seven goals.
Ah Van claimed another try for Vikings but they were well beaten.