Rugby: Hawke's Bay lock away Ranfurly Shield as wild scenarios emerge in Mitre 10 Cup Premiership

Hawke's Bay have locked away the Ranfurly Shield for the summer, seeing off a limp Wellington challenge with a 34-18 win.

In their first Shield challenge since 2014, Wellington were down 27-6 within 25 minutes, and now, additionally, sit at the bottom of the Mitre 10 Cup Premiership with one round to play, to be at risk of relegation to the Championship.

Their saving grace could be their final-round opponent — Championship cellar-dwellers Manawatū, with the Premiership battle fascinatingly poised going into the final round.

With their third successful Shield defence, Hawke's Bay are attempting to make the Championship far less interesting, having locked in a home semifinal against either Northland, Taranaki or Southland. Otago have also secured a home semifinal and will also play one of that trio, as five teams battle for the Championship title.

Hawke's Bay's victory over Wellington was sealed before halftime, with three tries in 12 minutes, with Wellington only able to muster two consolation efforts.

Wellington now need to beat Manawatū to boost their chances of avoiding sinking back into the second tier, but with just five points separating second-placed Tasman and Wellington, every team still has a chance of making it into the Premiership semifinals.

Auckland, who lead the Premiership by five points, are the only team assured of a spot, while Canterbury, tied with Wellington on 24 points, need to topple Auckland to ensure they don't get relegated, as a victory would almost certainly move them past either Bay of Plenty (26) or North Harbour (25), who play each other in the final round.

The only way a victory isn't enough for Canterbury to survive relegation is if an extremely unlikely event occurs where Bay of Plenty and North Harbour play out a draw in which both teams score at least four tries, and Canterbury don't get a bonus point.

That same wild scenario could impact Wellington, with there being individual scenarios in play where five teams end on 29 points, four teams on 28 points, or three teams on 34.

Waikato could have secured their semifinal spot with a win over Bay of Plenty, but after reeling off 27 unanswered points to take a 30-19 lead, they conceded an 83rd-minute try as Bay of Plenty kept their semifinal hopes alive, and gave their chances of avoiding relegation a big boost.

Taranaki sealed their spot in the Championship semifinals with a 35-19 victory over Manawatū.

Down 12-3 just before halftime, Taranaki scored four second-half tries to take an eventually comfortable victory and book a semifinal against either Hawke's Bay or Otago.