VIDEO: Highlanders triumph in South Island derby
In a frantic finish, the All Blacks' flyhalf, who shifts to England at the end of the season, stepped up after the Crusaders had narrowed the gap to two points with 25 minutes remaining.
The Highlanders scored three tries to two in the fast-paced, entertaining New Zealand derby as the defending champions Crusaders suffered a second successive loss.
It is the first time in three years the Crusaders have suffered back-to-back defeats, having gone down 19-29 to the Hurricanes last week.
"It was a hell of a game. We knew it was going to go down to the wire," said a relieved Highlanders skipper Ben Smith.
"We're still learning and it's still early in the competition. We just needed to make sure everyone was getting the right messages."
A key message was defence where the Highlanders only missed 15 of 131 tackles, half as many as the Crusaders.
The Highlanders led 14-10 at half-time, coming back after the Crusaders stole an early lead when George Bridge came off the blind wing at a line-out to punch through the middle of the Highlanders backline.
The Crusaders had their share of possession but struggled to make headway against the aggressive Highlanders defence in the first quarter.
First hooker Liam Coltman drove over for a try and then sustained forward pressure opened the way for Lima Sopoaga to score and with the flyhalf landing both conversions the Highlanders were up 14-7.
When the Crusaders sharpened their attack, they dominated the remainder of the half but their only reward was a penalty to Mitchell Hunt while misdirected passes and a contentious knock on decision cost them try-scoring opportunities.
"In a game like this you've got to take the chances you create," said Matt Todd who led the side in place of the injured Sam Whitelock.
"We felt if we could hold the ball we could create pressure… we created pressure but didnt get the points from that."
The Highlanders extended their lead early in the second half when prop Aki Seiuli, enjoying his first start of the season, paved the way for Elliot Dixon to score.
Manasa Mataele skilfully won a kick and chase to put Bryn Hall over as the Crusaders narrowed the score to 19-17 before Sopoaga's boot kicked the Highlanders to safety.
Man of the match: Codie Taylor had a strong performance for the Crusaders. Jordan Taufua was a force with ball in hand for the away side. Luke Whitelock's work rate was incredible once again for the Highlanders and Elliot Dixon showed his class at off the bench. However, the award goes to Highlanders flyhalf Lima Sopoaga, who made good decisions at No.10 and he was effective on attack once again.
Tries: Coltman, Sopoaga, Dixon
Cons: Sopoaga 2
Pens: Sopoaga 2
Tries: Bridge, Hall
Cons: Hunt 2
Yellow card: Waisake Naholo (Highlanders, 42 – foul play, high tackle)
Highlanders: 15 Ben Smith (co-captain), 14 Waisake Naholo, 13 Rob Thompson, 12 Teihorangi Walden, 11 Tevita Li, 10 Lima Sopoaga, 9 Aaron Smith, 8 Luke Whitelock, 7 Dillon Hunt, 6 Liam Squire, 5 Tom Franklin, 4 Jackson Hemopo, 3 Siate Tokolahi, 2 Liam Coltman, 1 Aki Seiuli.
Replacements: 16 Ash Dixon (co-captain), 17 Daniel Lienert-Brown, 18 Kalolo Tulioma, 19 Shannon Frizell, 20 Elliot Dixon, 21 Kayne Hammington, 22 Fletcher Smith, 23 Matt Faddes.
Crusaders: 15 David Havili, 14 Seta Tamanivalu, 13 Jack Goodhue, 12 Tim Bateman, 11 George Bridge, 10 Mitchell Hunt, 9 Mitchell Drummond, 8 Jordan Taufua, 7 Matt Todd (captain), 6 Heiden Bedwell-Curtis, 5 Luke Romano, 4 Scott Barrett, 3 Michael Alaalatoa, 2 Codie Taylor, 1 Wyatt Crockett.
Replacements: 16 Ben Funnell, 17 Chris King, 18 Oliver Jager, 19 Quinten Strange, 20 Billy Harmon, 21 Bryn Hall, 22 Brett Cameron, 23 Manasa Mataele.
Referee: Nick Briant (New Zealand)
Assistant referees: Mike Fraser (New Zealand), James Doleman (New Zealand)
TMO: Glenn Newman (New Zealand)
AFP & @rugby365com