Johnson played in both of Norwich City's matches against Derby last season, while he was still representing the Canaries, and he spotted their class even then.
Now, after completing a switch to the iPro Stadium, he is convinced that the team have what it takes to gain promotion to the Premier League, and he is looking to help the side piece together a winning run.
"I knew how good this team was before I signed," he said.
"I remember the games I played for Norwich against Derby last season. We drew both and Derby were right up there but they went on a bad run at the wrong time.
"At Norwich, we didn't have a great time at Christmas but when Alex Neil came in we went on a run. We really kicked on and found some consistency and that is the key."
Johnson's arrival at Derby has coincided with an up-turn in form for Paul Clement's side, after a disappointing start to the campaign.
The Rams took a while to click into gear, but they have collected two wins from their last two matches and are showing signs of why they are among the favourites to gain promotion.
Derby are currently sat in 10th place, but they are rapidly moving up the Championship table and will be aiming to continue on their upward trajectory this weekend.
Clement's side are still looking for their first home win of the campaign, and they take on Burnley on Saturday keen to give the supporters at the iPro something to cheer about.