Judge Kara DioGuardi said "Guess who is back- Siobhan."
Magnus, 19 from Cape Cod, was her quirky self as she blasted out crazy high notes in "Any Man of Mine."
Twain, mentor on the show this week, advised Magnus to "get into the song" and Magnus certainly listened.
Randy Jackson said, "I loved it. I loved the whole punk country look. I loved it, I loved it."
Ellen DeGeneres also loved Magnus' performance. "Way to pull the Shania Twain into the station."
"Great way to end the show, fantastic," said DeGeneres.
Normally not a Magnus fan, Simon Cowell's attitude changed this week- "I really really liked that song and I'm not normally a fan of country music."
He did however compare her signature scream at the end of the performance to "someone giving childbirth".
The judges liked most contestants except for show favorite Cyrstal Bowersocks.
Bowersocks, the only other female left in the competition aside from Magnus, was told by all four judges that it wasn't her best performance.
This is good news for Magnus.
The final five will be revealed live tomorrow night.