The fifteenth – and final – Idol will be declared on April 7

By Patrick Gomez
Updated March 24, 2016 10:10 PM
Credit: Ray Mickshaw/FOX via Getty Images

When it came to singing Sia songs on Thursday’s episode of American Idol, the show’s male contestants found themselves fearful to attempt the high notes from the singers vocally difficult songs.

Fan favorite MacKenzie Bourg – who wowed with a version of Whitney Houston‘s “I Wanna Dance with Somebody” earlier in the season – admitted her songs left him feeling out of his “comfort zone.”

But after a mentoring session with Sia, Bourg wowed with a version of “Titanium” and fellow competitor Dalton Rapatoni took “Bird Set Free” up from the key he had originally planned to sing it in. But it was Trent Harmon who received the highest praise from the judges for attempting the high notes on Sia’s “Chandelier.”

“Sia said, ‘Oh! You picked the hardest possible song, good for you,’ ” Harmon revealed after the feedback. “I wanted to make her proud.”

Keith Urban told PEOPLE of the performance afterwards: “Trent attempted one of, to me, the greatest songs out there and he killed it. We all know he can sing but he was pushed to a different level tonight.”

Meanwhile Harry Connick Jr. told PEOPLE: “It is really difficult to go out there and do what Trent did tonight. That was a very difficult song and he succeeded technically and, more importantly, he told a full story.”

For more on Idol, pick up PEOPLE’s The Best of American Idol collector’s edition issue, on sale now.

But it wasn’t a winning night for all of the Idol contestants. After ending up in the bottom the past two weeks, it was announced that Sonika Vaid – who saved herself last week with a performance of “Let it Go” from Frozen – had received the least amount of votes and was sent home.

“Before this competition, I never really thought I could pursue music as a career, but Idol has opened my eyes to the opportunity I have to pursue my passion,” she told PEOPLE afterwards. “And I plan on making the most of it.”

The Top 4 will perform next Thursday (at 8p.m. ET) and the fifteenth – and final – Idol will be announced the following week on a star-studded finale April 7.