Discarded All Blacks fly-half Stephen Donald scored all of Waikato's points in his side's opening 19-9 win over Southland in Invercargill on Friday.
Donald converted his own try and kicked four penalties to help the Mooloos to a deserved win over the Stags, who never looked like winning.
Waikato never relinquished their lead that saw last year's finalists up 10-0 after just 16 minutes, thanks to Donald's seven-pointer and a penalty.
The only try of the match came about after Donald took the ball quickly from a 5 metre scrum and managed to plant the ball for his 29th ITM Cup try after being hauled down just before the line.
Southland lock Josh Bekhuis and opposite number Romana Graham were then given their marching orders for a punch-up on the ground, which resulted in a penalty to the visitors which Donald duly converted.
Waikato had almost all the territory and possession in the first quarter but Southland got on the board after 23 minutes when newcomer Scott Eade kicked three points.
The rugby game turned into another boxing match as two more players - this time Ben May and Jason Rutledge - were yellow-carded for a bust-up.
A couple of punches were thrown by both front-rowers and it was briefly 13-on-13 in Invercargill.
Donald nailed the penalty - awarded for retaliation by Rutledge - but Eade nailed two more penalties for the hosts to take the scores to 9-13 in Waikato's favour.
The Stags failed to score any more points after the break, as Donald continued with his goal-kicking duties to seal the win with two more penalties.
Pens: Eade 3
Pens: Donald 4
Southland: 15 Robbie Robinson, 14 Mark Wells, 13 Kendrick Lynn, 12 Matt Saunders, 11 Glen Horton, 10 Scott Eade, 9 Scott Cowan, 8 Elliot Dixon, 7 John Hardie, 6 Alex Taylor, 5 Ben Nally, 4 Josh Bekhuis, 3 Chris King, 2 Jason Rutledge, 1 Jamie Mackintosh.
Replacements: 16 David Hall, 17 Nic Barrett, 18 Joe Tuineau, 19 Kaleni Taetuli, 20 Sonny Rangitoheriri, 21 James Lew, 22 Tim Cornforth, 23 Michael Peterson.
Waikato: 15 Trent Renata, 14 Sitiveni Sivivatu, 13 Save Tokula, 12 Jackson Willison, 11 Declan O'Donnell, 10 Stephen Donald, 9 Tawera Kerr-Barlow, 8 Alex Bradley, 7 Marty Holah, 6 Matt Vant Leven, 5 Romana Graham, 4 Toby Lynn, 3 Nathan White (c), 2 Aled de Malmanche, 1 Ben May.
Replacements: 16 Marcel Cummings-Toone, 17 Toby Smith, 18 Chris Middleton, 19 Zak Hohneck, 20 Brendon Leonard, 21 Tim Mikkelson, 22 Rena Schuster, 23 Ted Tauroa.
Referee: Garratt Williamson