The hard-running Leiua stands and holds the ball up in the tackle given his power, which buys precious seconds for his backline cronies to run off him.
Leiua was involved heavily early on and may be the answer to filling the void in the No 12 jersey, which hasn't been completely answered since Ma'a Nonu was sent packing at the end of 2011.
Bateman has performed admirably since joining the franchise but doesn't provide the punch with ball in hand that Leiua does.
Handling errors regularly dogged the Hurricanes during the contest as their progress was stymied due to their sloppy interplay.
Flying fullback Andre Taylor picked up the first try of the night when he linked nicely with Cory Jane who swatted a Beauden Barrett cross-kick in to Taylor's arms.
Watching Jane and Taylor unite will have been a pleasing sight for Hurricanes fans who hadn't seen the pair combine since 2012 due to Jane's injuries and Taylor's mixed form.
With a comfortable 16-6 lead late in the first spell, the Bulls hit back with a try from nowhere via Jurgen Visser who was on the end of some slick passing after Hurricanes lock James Broadhurst dropped an aimless bomb.
The Hurricanes took a 16-13 lead into the break, which didn't really reflect their dominance during the first spell but was more an indication of their inability to turn their territorial advantage into points.
The home side persisted with grubber kicks on attacking during the game as they tried to catch out a Bulls defensive line that was keen to rush up and smother the Hurricanes.
Utilising the grubber was a crafty play but it rarely paid dividends for the Hurricanes and as the second half rumbled into life they struggled to get any traction.
Leiua again looked lively in the lead up to the Hurricanes forcing the Bulls in to another infringement and when Barrett slotted his fourth penalty of the game, the Hurricanes had a 19-13 lead.
But that advantage was short-lived as replacement Handre Pollard danced through a gap and converted his own try as the Bulls hit the front 20-19 as the contest moved in to the final 10 minutes.
Barrett's reliable boot came to the fore again as he slotted a long-range penalty with only a few minutes left as the Hurricanes held on and then the All Black iced it after the hooter with another.
Hammett's side now have a bye before they host the Blues at Westpac Stadium on Good Friday.
Considering the Hurricanes have won their past two in a row, a week off may not be the best thing for them but they will be well-rested for when the Blues travel to the capital.
Hurricanes 25 (A. Taylor try; B. Barrett 6 pens, con)
Bulls 20 (J. Visser, H. Pollard tries; J. Louis-Potgieter 2 pens, con, Pollard con). Halftime: 16-13.
