Jordan Rhodes put the visitors ahead from the spot but the home side hit the front thanks to a Johnson strike and a Leroy Lita penalty nine minutes before the break.
Scott Dann levelled for Rovers after 71 minutes, before Johnson put his side back in front seven minutes later with his second impressive strike.
"He is a danger in that position. We say here that JJ will get you out your seat and sometimes he can dump you back in it as well that's the type of player he is. He was different class," he said.
"It's his day and that's what you want. He sets the tone, the standard; he has to do it again."
The win takes Jones' side to 50 points - three clear of Blackburn and the former Cardiff boss was not about to downplay the importance of their upcoming fixtures.
"We have got six cup finals. I've said it all along it could take 55 points, it could take as many as that.
"Everyone is fighting, it's such a tough division and it's getting harder and harder.
"They are all hard games - we showed a lot of character, a lot of determination and a lot of grit and that is what you will need, not just good play."
- Sports & Recreation