The Dogs lost a high-quality match to the Magpies after giving up nine of the first 12 goals, and Johnson said things had to change for next Sunday's match at the MCG.
"That's a good challenge for us next week, to make sure that we start well," he said post-match.
"We understand that no game's a given, and we've got to work extremely hard win any contest that we go in to.
"We had to fight our way back into the contest - they certainly got a good jump on us early.
"We worked hard - we certainly got our hands on it first, but then their intensity around the contest made us spill it out a little bit more than we'd like, and they were able to spread from that early on.
With the game played at a finals-like intensity, Johnson said he wasn't surprised to cop such a match in week one.
"It's round one and everyone's super-keen to get their first win on the board and get their season underway," he said.
"Now we've got a battle next week against the Tigers to do that."
Johnson had a fairytale 300th match against Adelaide two years ago when he kicked his side to victory with several late goals.
The 33-year-old's spot in this match - his 350th - had been in doubt for several weeks with injury concerns over his troublesome achilles, but he said he wasn't worried about not winning for the milestone.
"That's footy, isn't it? It certainly would have been nice to get victory today, there's no doubt about that.
"But not to be this time.
"No issue whatsoever with my injury, I hadn't felt it for a couple of weeks.
"I got through quite well."
Brad Johnson is a $431,400 forward in this year’s Toyota AFL Dream Team.
