Hawke's Bay will play Auckland next weekend, after continuing their fairytale season with a superb come-from-behind win.

They were down 24-35 heading into the least quarter, but their passion and commitment hit a breathless Waikato hard in the last 10 minutes.

Second-five eighth Sam Giddens cut them to ribbons with a brilliant solo try with just over 3min remaining to claim the match.

They had looked a forlorn hope after the 2006 champions asserted control in the third quarter, but they just kept the pressure on and it paid off.

Waikato had looked comfortable early, but had some dreadful lapses in the last 10min of the first half, with Hawke's Bay halfback Chris Eaton catching them napping with a sprint to the tryline from a base of a ruck 22m out.

Two booming 50m-plus penalties by first five-eighth Mathew Berquist helped take Hawke's Bay to a 21-11 lead at halftime.

Waikato stepped up a gear in the second half, with first five-eighth Stephen Donald landing an easy penalty 2min after the restart, while second-five Jackson Willison charged over for his second try after several phases of possession near the Hawke's Bay line.

They then took the lead with a try against the run of play, fielding a chip kick from Eaton deep in their own territory, and suddenly finding themselves with a four-man overlap after Donald sprinted 80m to score.

Hawke's Bay kept up the attack, with centre Jason Shoemark sprinting 40m before being brought down in the corner and Berquist kicking a penalty after repeated raids on the Waikato line.

But Waikato scored next, with No 8 Liam Messam's converted try putting them out to 35-24.

Then came Hawke's Bay's surge.

Tries to replacement centre Israel Dagg and then Giddens' brilliance in cutting the defence to shreds helped produce one of Hawke's Bay's most memorable victories in a memorable season.

Hawke's Bay 38 (Zac Guildford, Chris Eaton, Israel Dagg, Sam Gidden tries; Mathew Berquist 4 pen, 3 con) Waikato 35 (Jackson Willison 2, Liam Messam, Stephen Donald tries; Donald 3 pen, 3 con) Halftime: 21-11.