Theodore made 13 stops in the final period and has allowed only eight goals over 10 periods of work in the first-round series, enabling the Panthers to grab a 3-games-to-2 advantage over the Devils.
Tomas Kopecky added a short-handed empty-net goal to ice the win for Florida, which will attempt to close out the series with Tuesday's Game 6 in New Jersey.
Martin Brodeur yielded two goals on 32 shots for the Devils.
Scarlett Johansson steps out with fiance after pregnancy reveal
Susan Sarandon 'very excited' about daughter's pregnancy