The England full-back went unpunished for sliding in two-footed on Joleon Lescott in the dying minutes of the match, an incident which mirrored Vincent Kompany's sending off last weekend against Manchester United.
Despite the similarities between the incidents and City's staunch defence of Kompany, Blues boss Roberto Mancini insisted after the match that Johnson should have been sent off.
However, Gerrard expressed his belief the tackle was completely legal and criticised Mancini for attempting to get the defender into trouble for a challenge no worse than his own player's at the weekend.
When asked if he believed the tackle merited a red card, Gerrard told the BBC: “No I don’t think so, I think it was a clear winner of a tackle.
“But that surprises me really because [Mancini] has a go mid-week at Wayne Rooney trying to get his player sent-off and now he’s trying to get one our players into trouble, so I don’t think that works.”
The game itself saw the Reds take a 1-0 advantage into the second-leg, after the Liverpool captain converted from the penalty spot in the first-half.
And Gerrard was delighted to see his side pull through the first-leg unscathed with a goal to hand but was reluctant to declare the tie won just yet.
He continued: “It’s what we wanted to do, try to come here and try to get a clean-sheet and try to get a goal.
"But, there’s no way this tie’s over, we’re in for a very tough match in two weeks time, so the job’s half-done.
“We defended superb from back to front, we weren’t effective in the second-half, we know that, but we’re playing one of the big powers of the world and sometimes you’ve got to do the ugly stuff and we’ve done that tonight.
"Maybe the pretty stuff will come at Anfield in two weeks time.”
The Huyton-born midfielder was also pleased that his return from injury appeared to be going well after a 2011 in which he made just 15 appearances.
He added: “It’s nice to be back, I feel like a footballer again, I’ve had a difficult year. It’s games like this that I’ve missed, games like this that I’ve been patient for and work so hard to get back for.
"Tonight I got the winning goal, but it was all about the team tonight. It sets up for a cracking match with two fantastic teams.
"I thought we were better first-half, they were the better side second-half, but there’s till 90 minutes to play and I’m sure it’ll be a cracker at Anfield and it’s only advantage us, it’s still not over.”