Last night's episode of "Masterchef US" saw fan-favorite Katrina go home as she failed to impress judges Gordon Ramsay, Christina Tosi and Graham Elliot.

Season 6's episode 17 showed the remaining five contenders.  Titled "The Return of the Champions," winners from the past three seasons went back to take part in the pressure test that determined the contestant who will be sent home.

Katrina, Derrick, Stephen, Nick and Claudia all had to take part in a mystery box challenge to know who among them will be safe from elimination.

The infamous mystery box contained five different ingredients, which was assigned to each of the contestants. Stephen got the portobello mushrooms while Nick picked a brick of chocolate, reported Entertainment Weekly.

Derrick got blue cheese, which he seemed not to like. Claudia got a tomato and Katrina was assigned the pear.

The ingredients seemed simple, but Claudia's Hispanic roots were to her advantage as she was very confident in her dish and even had some time to be a bit flirty with Ramsay, who she admitted she dreamed about.

In the end, Claudia's Tomato Napoleon received the top marks from the judges as well as Stephen's and Derrick's dishes. Claudia was crowned the mystery box winner for the week.

The 31-year-old events manager from California was soon tasked to join past seasons' winners Christine Hu, Courtney Lapresi and Luca Manfè in assembling four boxes filled with 20 different ingredients, which the non-winners would prepare a dish from in the pressure test.

Christine came up with a basket filled with Asian-inspired ingredients. Courtney chose an exquisite baking box while Luca assembled one that had mainly Italian ingredients. True to form, Claudia came out with a Hispanic-inspired box of ingredients.

Derrick got Courtney's while Katrina received Luca's box. Claudia's box went to Nick and Stephen got Christine's pack of ingredients.

Stephen and Derrick were in good form and found the challenge a breeze while Nick's weak point was exposed. Meanwhile, Katrina struggled with the veal scallopini and needed Graham to boost her confidence. However, that was not enough to push her. In the end, she was sent home.

But Ramsay had a huge surprise for her. The judge told Katrina that when she is able to visit France, he will arrange for her to visit one of his restaurants as a guest so she'll learn a thing or two. Ramsay acknowledged the cook's passion and believed that a trip to one of his restaurants would let her learn and improve.

Next week's episode is called "Think Inside the Box," noted TV Guide. The remaining four contestants will be paired off to prepare an appetizer and entrée with the ingredients given by Ramsay and Elliot.

While the winners will be safe from elimination, the losers will compete in a pressure test to create Tosi's favorite chocolate-malted layer cake.

"Masterchef US" airs every Wednesday at 8 p.m. on Fox.