Much like the previous game, the Rangers raced out to a 2-0 lead in the first period before the Flyers sliced the margin in half heading into the first intermission.
Philadelphia went on to score three more times to take Game 2 by a 4-2 margin and even this best-of-seven set at one game apiece, but Lundqvist made sure Tuesday's lead held up, turning aside all 20 shots he faced over the final 40 minutes to stifle any hopes of another Philadelphia comeback.
Mark Streit scored the lone marker for the Flyers, who saw Ray Emery allow four goals on 20 shots before being pulled with just over seven minutes left in the third.
Emery made his third straight start in place of No. 1 goaltender Steve Mason, who made three saves in a surprise relief appearance. Mason wasn't expected to dress for the game as he continues to recover from an upper-body injury, but was named Emery's backup just hours before the game started.
The Flyers will look to even the series in Game 4 on Friday.