I was watching an episode of an anime. I came across a conversation which seemed to be confusing. The conversation was between two girls who were each other's competitors. Ursula and Dawn are the names of those two girls. Ursula and Dawn have taken part in a contest. Dawn wins the first round of that contest. After winning, she meets Ursula backstage and have a conversation.
The conversation was this-:
Ursula - My, My, what do you know? If it isn't sweet little Dawn.
Dawn - Ursula!
Ursula - I have the less than great pleasure of seeing your performance yesterday; as usual sheer dumb luck appears to have gotten you pass the first round. I hate to burst bubble but you are hardly capable of winning the final round. ----------------------------------------------------------------
The video link is here; the dialogue took place at 4:33 https://www.youtube.com/watch?v=k_ruXTg9Jfw&feature=youtube_gdata_player
I could not understand what Ursula meant by if it isn't sweet little Dawn. What did she mean to say? Is that an idiom?