Fantasia Barrino was on hand for the first group of "American Idol" Season 15 semi-finalist duets and pairing her with La'Porsha Renae seem like a no-brainer. But pairing them together to re-create Barrino's iconic "Summertime" performance from Season 3 was ingenious.

The two powerhouse divas took the stage by storm, providing one of the best duets of the entire night. It brought judges Keith Urban and Jennifer Lopez to their feet.

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"Watching Fantasia sing with somebody like La'Porsha, it's mind-blowing. Honestly, it's mind-blowing. You did a fantastic job," says J-Lo.

"It was the first one I've seen that's so beautifully matched. It's like an unstoppable force meets an immovable object. Fantastic," echoes Urban.

Harry Connick Jr. perhaps summed it up the best with his comments. "What that turned into was kind of what I was hoping it would turn into -- a battle of runs. And both of y'all killed it."

Posted by:Andrea Reiher

TV critic by way of law school, Andrea Reiher enjoys everything from highbrow drama to clever comedy to the best reality TV has to offer. Her TV heroes include CJ Cregg, Spencer Hastings, Diane Lockhart, Juliet O'Hara and Buffy Summers. TV words to live by: "I'm a slayer, ask me how."