In this week’s episode of “MasterChef,” it is the “Return of the Champions" as three previous winners help in the elimination challenge. Before that, the remaining contestants compete in the most difficult Mystery Box challenge of the season.

Gordon Ramsey calls up the remaining contestants, who he calls the “Magical Five.” Only Derrick, Nick, Claudia, Katrina and Stephen are left in the competition, which started with thousands of auditions.

The contestants randomly select a bench and they each find a different lone ingredient under their Mystery Boxes. Katrina receives a pear, Claudia a tomato, Stephen a Portobello mushroom, Nick a block of chocolate and Derrick gets blue cheese.

Out of all the contestants, Derrick is the most disappointed because he finds blue cheese very disgusting. However, he takes it like a man and get ready to cook. Everyone also receive a staple pantry box filled with common ingredients like flour, sugar, eggs, spices and heavy cream.

Katrina makes some glazed pears while Nick whips up a vanilla chocolate cupcake. However, the top three dishes belong to Derrick, Stephen and Claudia.

Derrick manages to overcome his initial hatred of the ingredient to produce some phenomenal thyme pretzels and blue cheese dip. Stephen let his creativity shine by making a Portobello mushroom sandwich with five iterations of the main ingredient. However, Claudia outshines all of them by digging deep in her Mexican roots.

Claudia wins the Mystery Box challenge with her savory tomato Napoleon made with crispy flour tortillas and roasted tomatoes. She gets the big advantage of being exempted from the elimination challenge. This effectively guarantees her spot in the top 4.

The judges bring Claudia to the pantry and tell her the good news. Not only is she in the top four, she also gets to control what her competitors will be cooking in the elimination challenge. She is given a basket where she puts in 20 Mexican ingredients. Meanwhile, the three visiting MasterChef champions also select ingredients for their own baskets.

Season 3 winner Christine Ha chooses a basket full of Southeast Asian ingredients, which Claudia assigns to Stephen. Season 4 winner Luca Manfe chooses a basket of Italian ingredients, which ends up with Katrina. Season 5 winner Courtney Lapresi’s baking basket is assigned to a Derrick while Nick gets Claudia’s Mexican basket.

Out of the four contestants, Nick is the most devastated because he has never cooked with Italian ingredients. He is visibly frazzled and runs around looking lost. However, he manages to turn things around. He whips up a dish of chorizo mussels and impressed the judges. He wins the elimination challenge unexpectedly.

Meanwhile, Stephen’s deconstructed pho tastes great but needs a little restraint. Derrick makes a chocolate pot de creme which tastes good, but the judges all thing he made it too heavy and safe.

Being a top competitor from the start, Gordon warns Derrick that playing safe may have bought him a ticket home. Luckily for him, Katrina really messed up her veal scallopini by serving it raw. She made a wonderful tagliatelle dish to go along with it, but the raw meat just did not cut it with the judges.

Katrina is sent home and leaves only Claudia, Nick, Stephen and Derrick to battle it out for the title of “MasterChef.” the series airs every Wednesday at 8:00 pm EDT on FOX.