The 3-1 win at Ashton Gate on Tuesday night left City firmly amongst the side's chasing a promotion play-off place.
"It was a great night for us," Johnson said after the match.
"I didn't think we did enough in the first half to deserve to be in front, but the lads kept going and it became a bit of a chess match with us changing our playing pattern to try to outwit them.
"We are keeping ourselves on the coat-tails of the leaders and I still believe we have the squad to maintain a challenge."