McIntyre's antics regularly attracted the attention of Riley when he should have been focusing on reducing the Canaries diving manoeuvres.
"That sending off changed the game," Rovers player-coach Bill Robertson said afterwards.
"At the same time we have to look at ourselves. If we adapted better we would have been able to take more control."
Robertson agreed his troops lacked the necessary urgency after a polished first 15 minutes when they started liked they finished during their away 4-2 Chatham Cup last 16 win against Tawa the previous weekend.
"Our urgency levels picked up when we were down to 10 men. I've got to congratulate Lower Hutt. They've achieved what they set out to.
"They came here to disrupt us and take away a point," Robertson said.
Rovers opened the scoring in the seventh minute when a penalty attempt by midfielder Ryan Tinsley beat Canaries keeper Coey Turipa.
The visitors equalised with an own goal 10 minutes later from Rovers striker Angus Kilkolly as he failed to pass a deflected penalty attempt to keeper Jonty Underhill.
For the remainder of the first half Rovers were far too conservative. They finished the first half with five shots on goal as did the Canaries.
In the second half the Rovers had 12 shots on goal, eight more than Lower Hutt.
While Greatholder displayed the benefits of his vast experience before given his marching orders, Robertson provided some much-needed defensive solidity when he took the field as a second-half replacement.
Striker Andy Bevin provided some quality touches throughout the game and midfielder Miles John again oozed class.
Robertson expects Greatholder to receive a one-week suspension in the wake of his red card and he will also miss the services of gutsy defender Stu Wilson for Saturday's away game against Tawa as Wilson received his fifth yellow card of the season yesterday.
Far too often the hosts persisted with the short-corner options which weren't working. Maintaining decent urgency levels should be on Robertson's whiteboard before this week's training.
An aggressive defender during his playing days with Celtic, Norwich City, Hearts and Falkirk, McIntyre, would have been pleased with the aggression his players displayed against more fancied opponents.
Striker Jean Carlo Estrada was always a threat on the break but like several of his teammates, overdid the dives.
Had they not placed a huge emphasis on this aspect of play they may have ended the Rovers' unblemished run at home.