Given the respective positions of these two clubs in the early League table, it would have been thought that the result was a forgone conclusion, but Lydney battled and fought hard in what was in large parts a dour game to watch, and they looked to be heading for a point, but it took a superb moment of class from the Swans to nick the points with an 82nd minute winner.
The first half was largely devoid of incident - With ten minutes on the clock, Raiyan Ahmed and Jack Smith combined to set up Jack W Smith but his effort was too high.
After Smith had another effort saved by Lydney Keeper Richard Thomas, efforts from Joe Stokes (blocked), and Jack W Smith (Header Wide) were the only other efforts of note in a half that saw Lydney work hard to nullify their opponents.
Just before the break, a clash of heads between Leighton Blacker and Keelan Hamblet saw both players replaced - Blacker with a nasty cut under his chin and Hamblet with a gash on the top of his head, but the first half ended with no goals and few other moments of incident to report.
Slimbridge's forced reorganisation at the half saw them claim the edge in the second period, and, on 54 minutes following a foul on Joe Shutt, Joe Stokes' free kick was too high as Slimbridge started to press.
Three minutes later, Ahmed's shot was deflected and saved by Thomas as Slimbridge started to create the better chances.
As the game entered the last 25 minutes, Jacob Rodgers was just unable to connect with a great a Stokes cross, and with 12 minutes remaining, a break down the Slimbridge right saw Rodgers play in Stokes, whose effort was saved.
The game turned on one 60 second passage of play with eight minutes remaining. Lydney had a free kick on the edge of the Slimbridge box, and the resulting kick saw a superb save and hold from Stephen Sarkodie.
He quickly released the ball upfield, and Charlie Mathews' cross from the Swans left flank found Ahmed in a dangerous position. He turned his man, and drilled the ball past Thomas to give the Swans the advantage.
Another new feature of this season is an increasing ability to score late and then see out games, and the Swans played out time without further incident to claim an important three points.
Slimbridge travel to Worcester Raiders on Monday (3.00pm), before their massive FA Cup game a week today with Dorchester Town (30th August, 3.00pm)
In the FA Vase, Longlevens beat Tuffley Rovers 2-0 to set up a next round meeting with the Swans which will take place on 20th September (3.00pm).
Team: Sarkodie, C. Blacker, (Rodgers 59) Mathews, Kang (Soule 73), Hitchings, Mara, L. Blacker (Shutt 45), Stokes, Jack Smith, Jack W Smith (Evans 90), Ahmed
Goals: Raiyan Ahmet 82
Supporters Club Man of the Match: Charlie Mathews