The battle rounds begin and the coaches enlist the help of their advisors: Adam Levine teams up with John Fogerty, Blake Shelton with Brad Paisley, Gwen Stefani with Selena Gomez, and Pharrell Williams with Missy Elliot. Coaches pit 2 singers from their team against each other in a dueling duet where the loser either goes home or is saved by an opposing coach using one of their two available steals. Those that remain will proceed to the knockout rounds. (thetvdb.com)