The table-topping and unbeaten Crusaders host the defending champion Hurricanes, who themselves have lost just once.
If the Hurricanes upstage their compatriots, it will open the door for the chasing pack to creep up on and perhaps even overtake the tournament's pace-setters.
Saturday, May 13:
Crusaders v Hurricanes
(AMI Stadium, Christchurch - Kick-off: 19.35; 07.35 GMT)
If you wanted to know how big this game is, then look at the ticket sales. They have build in additional, temporary, seating.
The sub-plot to this intriguing show is that Crusaders coach Scott Robertson was an assistant to Hurricanes mentor Chris Boyd at the New Zealand under-20.
The two men will know exactly how the other thinks about the game.
"I understand their [the Hurricanes'] philosophy about the game and how they want to play," Robertson told stuff.co.nz.
"I think the skillset of their players has shown how they want to play.
"They just play what is in front of them, and take opportunities that are given. So it has got to be on."
The Hurricanes, who have made a habit out of scoring with sublime crossfield kicks this season, are going to stick to their all-action approach.
"We've had some discussions and the coaching group will have some discussions before the game, but the players will make the decision on the field," Boys told stuff.co.nz.
He admitted the game will go down to the wire and the team winning the big moments will take the spoils.
"It's unrealistic to expect a team to play for 80 minutes right through, so there will be times when the Crusaders will be on top and there'll be times when we're on top and I think it'll come down to some critical moments."
2016: Hurricanes won 35-10, Christchurch
2015: Crusaders won 35-18, Christchurch
2015: Hurricanes won 29-23, Wellington
2014: Hurricanes won 16-9, Wellington
2014: Hurricanes won 29-26, Christchurch
Prediction: The Hurricanes have won six of their last eight games against the Crusaders, though only one of those victories came by a margin of greater than seven points. New Zealand derbies have seen an average aggregate points total of 49.6 points per game this season, the highest since 2012 (50.3 points per game). The Crusaders have won 11 of their last 12 games at home by an average margin of 27 points per game; however, their only loss in that span came against the Hurricanes in Round 17 last season. The Crusaders have won three of their last five games, including each of their last two, against New Zealand opposition despite having never lead at half-time in that period.The Canes have scored 24 tries in four away games this season, including 13 against Sunwolves in Round One. The Crusaders have conceded just 340 metres per game this campaign, fewer than any other team in the competition. The Crusaders have scored 10 tries when beginning possession with a kick return this season, more than any other team in the competition. The Hurricanes (17) and Crusaders (10) are two of just three teams (Lions, 12) to have scored 10+ tries in the opening quarter of games so far this season. David Kaetau Havili's 745 metres gained is the second most of any player in the competition and 141 more than any Hurricanes player. Ngani Laumape (22) is one of just two players (Courtnall Skosan, 25) to have made more than 20 clean breaks so far this season, Laumape is the top try scorer so far (11). To say it is a tough game to call is stating the obvious. We are going rogue and suggest the Hurricanes will sneak a late winner - by five points.
Crusaders: 15 David Havili, 14 Seta Tamanivalu, 13 Jack Goodhue, 12 Ryan Crotty, 11 George Bridge, 10 Richie Mo'unga, 9 Mitchell Drummond, 8 Jordan Taufua, 7 Matt Todd (captain), 6 Peter Samu, 5 Scott Barrett, 4 Luke Romano, 3 Owen Franks, 2 Codie Taylor, 1 Joe Moody.
Replacements: 16 Ben Funnell, 17 Wyatt Crockett, 18 Michael Alaalatoa, 19 Quinten Strange, 20 Heiden Bedwell-Curtis, 21 Bryn Hall, 22 Mitchell Hunt, 23 Manasa Mataele.
Hurricanes: 15 Jordie Barrett, 14 Cory Jane, 13 Vince Aso, 12 Ngani Laumape, 11 Julian Savea, 10 Beauden Barrett, 9 TJ Perenara (captain), 8 Brad Shields, 7 Ardie Savea, 6 Reed Prinsep, 5 Vaea Fifita, 4 Mark Abbott, 3 Jeffery To'omaga-Allen, 2 Ricky Riccitelli, 1 Chris Eves.
Replacements: 16 Leni Apisai, 17 Ben May, 18 Loni Uhila, 19 Sam Lousi, 20 Toa Halafihi, 21 Te Toiroa Tahuriorangi, 22 Otere Black, 23 Wes Goosen.
Referee: Jaco Peyper (South Africa)
Assistant referees: Mike Fraser (New Zealand), Cam Stone (New Zealand)
TMO: Glenn Newman (New Zealand)
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