Wing Leicester Fainga'anuku scored three tries for the Christchurch-based Crusaders who held on to beat the Auckland-based Blues 34-28 in a fourth-round match which reprised last year's final in Super Rugby Pacific.
The Blues came close to winning the match with late tries but lock James Tucker and backrower Hoskins Sotutu both lost the ball when they were over the Crusaders line.
It was the marquee match of the round and mostly lived up to that billing.
But both teams were guilty at times of errors and lapses of discipline; poor kicks, dropped ball and missed first tackles all added to the tension for the respective coaches.
The Crusaders' set piece edge and tenacity in defence in the last 15 minutes finally made the difference. Down to 14 men at a crucial stage, they fought bravely to defend their own line.
"I think in the first half we might have had the better of that half and then the Blues threw everything at us and we were lucky to get away with it really," Crusaders captain Scott Barrett said.
The Blues opened the scoring in the seventh minute from winger Mark Telea who shrugged off tackles, broke into space and dashed over from almost halfway. Telea and fellow winger Caleb Clarke had a major role in the game with their powerful running.
Fullback Fergus Burke replied for the Crusaders in the 14th minute, then Ethan Blackadder scored to give the Crusaders their first lead at 12-7 after 21 minutes.
The Blues wrested back the lead with a try to Clarke and went out to 21-12 with a try to Roger Tuivasa-Sheck.
Fainga'anuku scored twice before halftime to put the Crusaders back in front and they went to the break leading 24-21.
The second try was part of the pivotal moment in the game.
Blues replacement prop Jordan Lay was sin-binned and with no other replacements the teams had to go to uncontested scrums and the Blues were reduced to 13 men.
With the Blues two men down, Fainga'anuku strolled almost unopposed immediately before halftime and scored again in the fifth minute of the second half as the Crusaders took their biggest lead at 31-20.
A try to Stephen Perofeta narrowed the gap but the Crusaders held on with the help of a penalty from Richie Mo'unga.
Crusaders 34 (Fergus Burke try 16min, Ethan Blackadder try 21min, Leicester Fainga’anuku 3 tries 32min, 37min, 46min; Richie Mo’unga pen, 3 cons), Blues 28 (Mark Telea try 7min, Caleb Clarke try 24min, Roger Tuivasa-Sheck try 28min, Stephen Perofeta try 55min; Beauden Barrett 4 cons). Ht: 24-21.
BLUES (1-15): Alex Hodgman, Ricky Riccitelli, James Lay, James Tucker, Cameron Suafoa, Adrian Choat, Dalton Papalii (c), Hoskins Sotutu, Finlay Christie, Beauden Barrett, Caleb Clarke, Roger Tuivasa-Sheck, Rieko Ioane, Mark Telea, Stephen Perofeta
RESERVES: Soane Vikena, Jordan Lay, Nepo Laulala, Tom Robinson, Taine Plumtree, Taufa Funaki, Bryce Heem, Zarn Sullivan
CRUSADERS (1-15): Joe Moody, Codie Taylor, Tamaiti Williams, Scott Barrett (c), Sam Whitelock, Ethan Blackadder, Tom Christie, Sione Havili Talitui, Mitch Drummond, Richie Mo'unga, Leicester Fainga'anuku, Dallas McLeod, Braydon Ennor, Sevu Reece, Fergus Burke
RESERVES: Brodie McAlister, Kershawl Sykes-Martin, George Bower, Zach Gallagher, Christian Lio-Willie, Willi Heinz, Pepesana Patafilo, Macca Springer
Referee: James Doleman
Assistant referees: Jono Bredin, Fraser Hannon