The Bermuda forward reacted first to team-mate O’Brian Woodbine’s throw in which he controlled with his first touch before curling a left-footed shot into the top left corner.
“I’m just thankful to get the win,” he tweeted.
Lewis’s 71st-minute strike was his second of the season after opening his account in a 2-1 home win over Hartford Athletic last month.
Swede Ian Svantesson opened the scoring in the 21st minute with his third goal in four matches.
Lewis and Svantesson have evolved into a lethal attacking pair, having been involved in five of their team’s six goals this season.
“They are both capable of scoring ten-plus goals this season”, Mike Anhaeuser, the Charleston coach, said.
The shutout win was Lewis and his teammates’s first of the season.
“It feels great to get the shutout and Joe (goalkeeper Joe Kuzminsky) deserves the clean sheet,” Anhaeuser added. “We felt like we’ve been robbed the past few weeks with the late goal against North Carolina and the late penalty against Hartford.
“I was proud of how organised we stayed after the first goal, it’s a rivalry game and I’m very proud of the guys.”
Lewis was playing in his second match since returning from international duty with Bermuda last month.
The 23-year-old scored in Bermuda’s 3-1 win away to Dominican Republic in their final Concacaf Nations League qualifying match.