Instead goals from Paddy Madden, Ed Upson and Dan Burn secured the Glovers' fifth straight league victory - and condemned the visitors to only their second league defeat in 16 matches.
Rosler said: "I think we were the far better team in the first 35 minutes, but we made one mistake and they punished us straight away. We had six or seven chances to take the lead.
"In the last month we have had three or four goals scored against us from shots outside of the box which have gone into the top corner. It's was a great bit of individual skill.
"The game was lost after the second goal. You have to score in your good periods and we had so many chances in the first half. We had to take at least one of them.
"They were more clinical than us, and in the second half Yeovil were defensively very solid. We didn't create enough and our set-pieces were not good enough.
"The longer the game went on the more the pitch cut up and it was difficult to play our game. They beat MK Dons this way and now they've beaten us. If this was a Premier League pitch I don't think the game would have gone ahead."