With a rampaging display by the forward pack, Johnson's educated boot was the decisive factor in the match, with his pinpoint accuracy putting the Panthers under huge pressure on a sodden night.
By contrast, Panthers half Luke Walsh was under such pressure that simply getting his boot to ball late in the tackle count represented a significant success. With the Warriors controlling the ball and Russell Packer, Ben Matulino and Feleti Mateo tearing off huge yards up the middle, it should have been a comfortable outing.
The trio combined for a whopping 582m. Matulino led the way with 233m from 22 carries, while Packer rumbled for 172m from 17 bruising carries.
"It was a pretty tough win in pretty miserable conditions," Packer said. "Hopefully we can build a bit of momentum off it.'
While the first-half slip-up was a concern, the Warriors will be buoyed by the way they rebounded.
"That has been one of our downfalls so far this year," Packer said. "We have probably looked like the best team for a good part of the majority of games but we've had little lapses of concentration or whatever it is and allowed the opposition back into the game.
"That's what happened 10 minutes before half-time but I am glad we bounced back. We probably learned some lessons from our last few games. It was a good, tough win."
A piece of Panthers charity handed Konrad Hurrell a try that put the Warriors' noses back in front and James Maloney crossed from a neat Mateo pass to give them some breathing space before Kevin Locke capped his return with a try on the hooter.
Early on the Warriors made light of the conditions, completing 13 of 14 sets. Their first try came courtesy of a bad Lachlan Coote fumble, while the second required sure hands from Vatuvei as he pounced on Johnson's inch-perfect grubber.
At that point the only concern was the fitness of hooker Alehana Mara, who limped off with an ankle injury.
Then an intercept by Panthers winger Josh Mansour ended in a try.
Walsh sent Kevin Kingston over for a try to level the scores, before Brad Tighe stepped past Hurrell with worrying ease to race 60m before Lewis Brown pulled off a try-saving tackle. The reprieve was only temporary, however, with Geoff Daniela waltzing through the dishevelled Warriors line.
Another full-scale Warriors meltdown seemed on the cards but they rallied admirably, shutting the Panthers out for the remaining 45 minutes for their second road victory.
