The Crusaders have beaten the Chiefs 25-20 in the Super Rugby Pacific final to claim a fifth straight title and send coach Scott Robertson and veterans Sam Whitelock and Richie Mo'unga off as champions.

The Crusaders were the first to score, with first-five Mo'unga kicking a penalty goal in the ninth minute following a string of three straight penalties against the Chiefs.

The Chiefs then immediately lost All Blacks midfielder Anton Lienert-Brown to a yellow card for making head-on-head contact with Crusaders wing Dallas McLeod, with the latter sent for a Head Injury Assessment, which he would fail, ruling him out of the rest of the match.

Discipline was a problem early for the Chiefs, with co-captain Sam Cane given a warning after his side gave away six consecutive penalties in the first 15 minutes.

The Chiefs got Lienert-Brown back and pushed into Crusaders territory. They would come away with points, with Damian McKenzie kicking a penalty goal to level the score 3-3.

The home side then got their tails up and Luke Jacobson produced a crunching tackle on Will Jordan before stealing the ball to put the Chiefs on attack.

The made the most of their chance, with a brilliant pass putting Shaun Stevenson into a gap and the star fullback, who missed selection in the All Blacks Rugby Championship squad, outpaced Mo'unga to score the first try of the game.

McKenzie converted to push the Chiefs out to a 10-3 lead.

However, the hosts discipline would again let them down and they were penalised at the ruck and had another player sent to the sin bin for repeated team infringements, this time Jacobson, with the Crusaders striking almost immediately as Codie Taylor barged over from a lineout drive.

Mo'unga missed the conversion to leave the score 10-8 to the Chiefs.

The Chiefs had the next scoring chance, but McKenzie missed his penalty goal attempt.

With Jacobson in the sin bin the Crusaders went wide and broke down the left through Leicester Fainga'anuku.

Mo'unga barged over from the resulting play, scoring the defending champions second try in the 36th minute.

The All Blacks playmaker duly kicked the conversion as the Crusaders went ahead 15-10 and they had a chance to build on that lead on the stroke of half-time but missed a penalty attempt.

The Chiefs were back to the full fifteen and the first to strike in the second half, scoring a try down right touchline to new All Blacks wing Emoni Narawa.

McKenzie converted as the hosts took back the lead 17-15 and he would keep the scoreboard ticking over soon after with a penalty goal to extend their advantage to 20-15.

Narawa scored what looked like a brilliant Chiefs try but it was disallowed and the Crusaders given a penalty for McKenzie encroaching inside the 10m during the preceding lineout.

The Chiefs then produced some desperate defence to repel the Crusaders lineout drive to stop the visitors from scoring.

The breakdown was a brutal place to be with both sides upping the ante in the second half and plenty of big tackles and heavy collisions on offer.

The Crusaders lineout drive was a threat all night and they went to it again with ten minutes to go with the commentators describing the tactic as "ground and pound".

Another Crusaders assault on the Chiefs line resulted in Cane being penalised and sinbinned in the 72nd minute and the Crusaders pounced, scoring from another lineout drive to level the score at 20-20.

Mo'unga had a tricky conversion from the sideline to give the Crusaders the lead and he slotted it to put the defending champions ahead with just minutes remaining.

McKenzie took a long range penalty goal in the 77th minute but came up short and ultimately the Chiefs title challenge would too, as the Crusaders kicked another penalty to seal a 25-20 victory and a fifth straight Super Rugby title.

Discipline was ultimately the Chiefs undoing with the hosts on the wrong end of a lopsided penalty count and they will have to wait another year for their chance to lift the trophy.

The win caps a fairytale last season with the Crusaders for coach Robertson and All Blacks Sam Whitelock and Mo'unga, with the final their last match for the Canterbury-based team.

Robertson is the next All Blacks coach while Whitelock and Mo'unga are heading to France and Japan respectively after this year's World Cup.

The Crusaders have now won 12 Super Rugby titles overall.