Lee Cook found the net on the hour at the County Ground to give the O's their first points of the season.
"It was a really solid performance. It was worth waiting for," Slade told BBC Sport.
"All of a sudden, from a gloomy start to the season where we played three and lost three, we have now won a game.
"We have a game in hand and two home games to come, so the place is a little bit brighter."
Orient continue their League One campaign on Thursday at home to Brentford.