The departure of the 17-year-old Fayetteville, Ga., resident narrowed the number of "Idol" wannabes to four. The winner will be crowned May 25.
Contestants sang two songs — one from the year of their birth and one from any Billboard chart's current top 10 — in Tuesday night's program.
Though judges Randy Jackson and Paula Abdul praised Bennett's funky take on Prince's 1988 hit "Kiss," judge Simon Cowell derided it as "screechy" and "annoying."
In a turnaround, her second performance — a cover of Mary J. Blige's "Be Without You" — was deemed "pitchy" by Jackson but well received by Cowell.
"I think she did rather well with that," Cowell said.
Elliot Yamin, 27, had the next-lowest vote total.
Cowell offered typical sugar-free criticism on Tuesday's program, saying Yamin's rendition of "On Broadway" was "disjointed." He also said he was "just a little bit concerned" following his cover of Michael Buble's "Home."
"I'm not sure I would have chosen the lyrics, 'I want to go home,'" Cowell told Yamin.
Nearly four years since its debut, "Idol" continues to rule the ratings. It has attracted 25 million to 33 million viewers each telecast this season.
Host Ryan Seacrest said on Wednesday's program that viewers called in nearly 46 million votes.