Marcel Vigneron and Brooke Williamson tackle high-end and humble ingredients as they fight to compete in the finale.

Brooke Williamson competes to keep Mike Isabella out of the running for a place in the Top Chef Duels finale.

Mike Isabella and Stefan Richter face off – after going on a field trip to get their ingredients.

Mike Isabella and David Burke face-off with processed ingredients as Mike tries to keep David out of the finale.

Mike Isabella and Tiffani Faison recreate past Top Chef challenges as Mike tries to keep Tiffani out of the finale.

Tiffani Faison and Nyesha Arrington must cook with market items selected by Los Angeles food editor Lesley Suter.

Kristen Kish tries to defeat Tiffani Faison at a challenge after Wolfgang Puck's heart – the omelet.

Kristen Kish tries to keep the final chef Art Smith out of the finale with a vegan/raw challenge.

The chefs who have won their episodes of The Knockout compete to gain a spot in the finale of 'Top Chef Duels.'