Stoke led for 65 minutes at Bournemouth but couldn't find a second goal to kill the game off – and then couldn't stop the hosts' two subs turning the game on its head.
If you can't do the first, says the keeper, at least make sure the opposition can't do the second.
“We were good for 70 minutes then there were five or 10 minutes of madness," said Butland.
“They got a lucky break with the first goal but then we've still got to do better with it – then the bread and butter that you work on, defending free-kicks, you've got to deal with it. We let too many runners go and they were queuing up at the back post for it.
“We were in a good place but at 1-0 you're never safe. You've got to find a way to kill it or to grind it out. Unfortunately we did neither."
“I thought he was excellent," Lambert enthused. “What a debut that was, I thought he was brilliant.
“It was his first training session for about 10 days (on Friday) and even then it was a kind of walk through because of playing on the Wednesday. But I thought his level was excellent.
“I knew fatigue would set in with the lad in his first game and he's got a yellow card, so with fatigue he could mis-time a challenge and then you're down to 10 men and lose him for the following game.
“It was the right thing to do for him (subbing him in the 71st minute) because of the way was going.
“He will have a good week this week coming and what you see there, there will be a lot more of that to come."