The Blues brought too much pressure with their game, so they needed respect all over the park, he said.
Thorn said he was impressed with the job his former Crusaders and All Blacks teammate Leon MacDonald had done with the Blues.
"They're the best team we've played of the Kiwi sides, they can strike anywhere. They are doing all the little things I don't reckon they did so much in the past. They're doing them and competing hard.
"They're a very good football side and you've got to dip your hat, they're going to be really strong at home [in the playoffs]," he said.
"It wasn't good enough from us defensively.
"We showed offensively that when we get down there we can gain some points. We let ourselves down. We weren't connected. There was holes opening up, there was one-on-one tackles and you can't win game, or get in the contest, with that," he said.
At halftime, the Reds were still in the game, but the Blues scored two quick tries to claim the momentum.
"We've been in every game – that's probably the frustrating thing this year," he said.
"New Zealand sides strike well, and they strike quick, so if that's the challenge in the next two or three weeks, we've got some work to do there."
If they could get their defensive side of the game right, they had the ability to challenge sides, he said.
Captain and halfback Tate McDermott said if you gave a team like the Blues an opportunity, they took it, and that was the difference.
"Their ability to create those mismatches with their forwards, get those backs early ball, they've got a world-class backline and it comes down to their execution," he said.