“Not a chance! I've got this one in the bag.”
You're playing tennis against a friend. You like to tease each other. He says that he's going to beat you. You boast that you're going to win.
Not a chance! I've got this one in the bag.
"Not a chance!" is a creative way of saying "No" or "That's not possible."
A: Do you think it's possible that the sales team will hit their target for fourth quarter?
B: No way. Not a chance!
This is a casual expression, good for spoken English, friendly emails, text messages, and so on.
If you strongly think someone is going to win a competition or contest, you can say that they've "got it in the bag".
Use this expression to talk about sports, business deals, job applications, etc.