3. Challenging Neuvirth: In his first playoff start in nearly five years, Flyers goaltender Michal Neuvirth made 31 saves. But he wasn't really pressured on the 19 shots on goal he faced during the first two periods; many of them came from the outside with little traffic.
When the Capitals stepped up the pressure and got to the net more frequently in the third period, they got a rebound goal from T.J. Oshie and generated several other quality scoring chances. They'll need to do more of that against their former teammate in Game 5.
4. Discipline and structure: One of the keys to the Flyers' Game 4 victory was how they were able to play a physical game while cutting down on the number of penalties they took. After giving the Capitals nine power plays and allowing five power-play goals in Game 3, the Capitals had two power plays in Game 4, one for 28 seconds.
The Flyers' physical play also helped them generate sustained pressure in the offensive zone and control play for much of the first two periods. They had 22 of their 43 hits on Capitals defensemen, including 11 on Matt Niskanen.
"They've got such highly skilled [defensemen] back there," Flyers forward Ryan White said. "If you let them go untouched, they're going to embarrass you. They can all move the puck, they can all skate. That's been the goal since Game 1, just keep wearing them down, keep pounding them, keep making them turn and go back for pucks hard, and make them make plays."