American Idol” marked its 400th episode Wednesday night, and the milestone was highlighted with a sensational performance by 16-year-old Jessica Sanchez.

The San Diego high school student earned a standing ovation from the judges, belting out a flawless version of the late Whitney Houston’s signature hit, “I Will Always Love You.”

“You not only are the best vocal of the night, I think you are one of the best singers in the competition,” judge Randy Jackson declared. “This is what it’s really all about, finding the best talent in America–and America, this is one of the best talents in the whole country.”

Judge Jennifer Lopez was almost left speechless, while judge Steven Tyler told the teen, “Jessica, you may be the one. You just made 40 million people cry.”

Wild card Erika Van Pelt also impressed the judges, singing “I Believe in You and Me” from Houston’s 1996 film, “The Preacher’s Wife.”

“You’ve got that unbelievable tone and you can sing anything,” said Jackson. “That was amazing by the end – amazing.”

Lopez got her “goosies” before Van Pelt even started to sing, “The tone of your voice and the fullness of your voice really, really makes songs come alive.”

Hollie Cavanagh sang Houston’s "All The Man That I Need," which earned high praise from Jackson. “Dude, you nailed it.”

“That was beautiful,” cheered Lopez. “That’s the Hollie I know from last year and this year.”

Skylar Laine was another standout, putting a country spin on Houston’s 1988 hit, “Where Do Broken Hearts Go.”

“You gave us our biggest moment of the night,” Lopez raved after mildly criticizing Laine’s “nasal-y” start.

Not all the girls shined.

A miffed-looking Elise Testone struggled through Houston’s “I’m Your Baby Tonight,” while Shannon Magrane clearly suffered from a bad case of nerves during her shaky attempt at Houston’s “I Have Nothing.”

The boys managed to turn out more consistent performances during the two-hour live show, drawing from Stevie Wonder’s songbook.

Joshua Ledet sang a gospel-inspired version of “I Wish,” while wild card Jermaine “Gentle Giant” Jones crooned “Knocks Me Off My Feet” with his signature baritone voice.

Phillip Phillips performed acoustic guitar while singing his unique take on “Superstition,” as wild card DeAndre Brackensick took inspiration from Jamacia with his reggae version of “Master Blaster.”

Even Heejun Han managed to disarm Jimmy Iovine with his soft, slow and sincere version of "All in Love is Fair.”

“You know what? He won me over tonight,” admitted the chairman of Interscope-Geffen-A&M.

But by the end of the show, it was clear that it was ladies’ night–or at least, one specific lady’s night.

When host Ryan Seacrest asked Tyler who his top two picks were from the thirteen finalists, the Aerosmith frontman answered without hesitation, “Jessica Sanchez and Jessica Sanchez.”

Up next: A twist! After the audience vote determines the lowest-ranking male and female singers, the judges will ultimately decide who gets the axe.