The Gers took the lead in the game through a Carla Boyce header, but City found their way back into the tie just before the break and went on to progress to the final with a 4-1 victory.
Vignal said: “We knew it would be a difficult game against a strong team so I thought we played well in the first-half.
“Of course when you play City you everybody knows it will be a tough game, but we tried to play on the floor and we tried to play a good pattern of play and they respected the game plan after a couple of mistakes but they will learn from this.”
With some good victories in the cup to get the Gers into the semi-final, Vignal believes his side are continuing to progress each game.
He added: “Getting the opening goal today showed progress. When you play a team like City you need to be really realistic and we lost discipline a little bit in the second-half that’s why we conceded goals and they are really strong at set-pieces.
“Next year will be completely different, it will be a new season and a new start, fresh faces but we tried our best.”