"It doesn't get any harder than that," Kirwan said. "For us it was an incredibly brave effort but our discipline really let us down.
"The boys and I felt we were still in the game late, but our discipline let us down starting with that red card."
Kirwan said he was still looking for footage of the incident, one that is likely to see Triggs suspended for at least one week.
"He retaliated to an elbow to the nose," Kirwan said of Triggs' explanation. "His nose was pretty messed up so he retaliated which you shouldn't do. We're just trying to get the footage to see what happened but you can't do that sort of stuff."
Kirwan said his team, now with two losses after two matches and second to last on the table, could take plenty out of their defeat.
"I think they played their hearts out for each other so we can take that out of the game. We've got a pretty tired changing room.
"I felt the boys adjusted the game well. We kicked for territory but I just felt that even with 14 men we were still in the game with 15 to go. I don't know what was happening but the penalty count was something like 15-5. You can't win a football game with 14 men with that sort of penalty count against you."
He said Steven Luatua was still being examined after he left the field in the first half, but the big loose forward had potentially dislocated his shoulder.
"We're confident that what we're doing is heading in the right direction," he said of the Blues. "We just have to stay tight and grind out that win."