Things started horribly for the visitors when Leonardo Gonzalez was shown a straight red card by referee Ismail Elfath just seven minutes in for a rash challenge on Columbus' Ryan Finley.
Despite being down a man, Seattle used a well-executed set-piece to go in front in the 14th minute as Mauro Rosales whipped a free kick into the box and it was headed home by Johnson for his seventh goal of the season.
Columbus failed to generate many scoring chances over the duration of the 90 minutes and came out on the wrong end of the score line for the fifth time in their last seven league outings.
Seattle, meanwhile, posted a second consecutive clean sheet and continued its surge toward the playoffs with a fifth win in its last six opportunities.
08/31 23:19:29 ET