With Canadian Idol just weeks away from crowning its newest champ, the final four competitors proved their musical fortitude Wednesday night as they performed standards once perfected by legendary crooners whose renditions have stood the test of time.

Upping the ante, the show tested the endurance of the singers as they each delivered their own versions of two popular standards accompanied by sophisticated rhythm of a live 20-piece orchestra.

Kicking off Canadian Idol's cocktail hour, Theresa Sokyrka utilized her jazz vocal training, jiving to her own rendition of "It's Only a Paper Moon."

Showcasing her trademark scatting, Sokyrka impressed the judges, as well as the audience who got up on its feet for the first of many standing ovations throughout the night.

Bowled over by her performance, Jake Gold said, "We all believe in you."

"When that right shoulder starts bouncing, it's all over," Farley Flex said.

Sokyrka's second song, "Dream a Little Dream of Me", also got positive reviews from the judges except for one highly unpopular comment -- judging by the audience's boos -- from Zack Werner who thought the singer needed the help of a "serious" vocal coach.

"You're this much short of being really wonderful," Werner said, putting his thumb and index finger together to illustrate his point.

Next on the bandstand, Kalan Porter eased into the ballad "Moon River", his delicate phrasing of the first few lines guided by a solo guitar.

The 18-year-old's delivery was a hit with the judges who showered compliments on the singer.

"What a treat to hear that smooth, syrupy side of your voice," Sass Jordan said.

Porter continued to have a stellar night with his second performance as he crooned the popular ballad, "The Way You Look Tonight."

Dressed in a dark pin-striped suit, Porter romanced the crowd and won the judges over with his soulful and snappy take on the song made famous by legends such as Frank Sinatra and Tony Bennett.

"It's like you were taken over by the soul of a matinee idol from the 50s or the 40s. Fantastic, kiddo," Jordan said.

"It was smooth," Werner remarked.

Idol's own "ol' blue eyes", Jason Greeley, became the surprise hit of the evening, giving a spirited version of Sinatra's "I Won't Dance".

From the rock bar to the cocktail bar, Greeley seemed to surpass the judges' expectations with his style and showmanship, receiving a standing ovation not just from the crowd but, also, from Gold and Flex.

"I think we just found out what kind of singer you are. You're a big band singer," Gold expressed.

"I'm so impressed. I tip my hat to you," Flex said.

Greeley's second song, however, split the judges' decision on his version of "It Had to Be You".

While Jordan was pleased with the singer's efforts, Gold thought it was not his best performance.

Though Werner commended Greeley for his stage presence and dapper appearance, he believed the 27-year-old didn't "excite the house" as well as the other competitors.

Rounding off the quartet of Idol crooners, Jacob Hoggard popped out from behind the orchestra with matching white bow tie and suspenders.

Adding fancy footwork and lively facial expressions to his performance of "Straighten Up and Fly Right," Hoggard seized the attention of the panel, which doled out nothing but rave reviews.

"You're a star, bro," Werner commented.

"You're an entertainer extraordinaire," Flex said.

Hoggard continued to bring on the accolades with the rendition of his second song, "Unforgettable" -- a Nat "King" Cole classic, which Gold called "fantastic."

Jordan, on the other hand, simply used the song's title to describe Hoggard's performance.

Canadian Idol continues its salute to the standards with group medleys by the Top 4 and a special performance by crooner Matt Dusk on Thursday 8 p.m. ET. Voting results which determine the final three competitors will also be revealed live on the hour-long episode.