Prop Ofa Tuuangafasi became just the fifth All Blacks player to be sent off in a test on Saturday when he was given a red card for a high tackle on Wallabies winger Tom Wright in the 24-22 loss to Australia in Brisbane.
"We just have to be better," Coles told reporters on a conference call on Monday.
"We do a lot of tackling practice in the week. We just have to lower our sights and targets to not get those red cards again.
"I suppose it's one on the chin for us."