Villa, who had won their first four matches of the campaign, now host Southampton on Sunday with Watkins looking for a swift response.
“Friday's result does not determine us for the season. It is our first loss and it is how we bounce back," said the striker.
“We just need to focus on the next game now. Obviously it is hard and I know it is probably not what people want to hear. They are probably annoyed after the defeat.
“But we have had such a good start to the campaign and we have to try and regain that momentum going into the Southampton game."