Leiua crossed in the 74th minute to settle a see-saw contest after Faifili Levave, TJ Perenara and Julian Savea had also gone over for the Hurricanes with Beauden Barrett booting nine points.
Johnny McNicholl responded with two tries for the Crusaders while Colin Slade also registered a score and Tom Taylor added 11 points with the boot.
Barrett kicked the Hurricanes ahead in the seventh minute and it was 10-0 three minutes later as Savea brushed aside the challenge of Kieran Read and offloaded to Levave who crossed in the corner. Barrett added the extras.
The Crusaders got on the board through Taylor but the Hurricanes had their second try moments later as they drove forward from a lineout and Perenara scored from the resulting ruck.
Barrett once again slotted the conversion and the Hurricanes had a commanding 17-3 lead after just 21 minutes.
The Crusaders were in danger of getting blown away but crossed for their first try before the half hour when McNicholl pounced on Ryan Crotty's grubber kick with Taylor converting.
And they had the lead before the break as, after several good phases, Slade slung the ball out to McNicholl for his second try and Taylor, despite missing the conversion, nailed a second penalty minutes later to make it 18-17.
That advantage would not last long, though, and the second half was just three minutes old when Savea touched down after chasing down his own kick with Barrett converting.
Slade narrowed the gap to just a point as he went over out wide and when Taylor booted his third penalty of the game with 15 minutes to go the lead had changed hands again.
But Leiua was to have the final say in stunning fashion as he gathered the ball around halfway and used his pace to beat four prospective tacklers before crashing over for the deciding score.
- Sports & Recreation
- Tom Taylor
- Julian Savea
- Colin Slade