Nicklas Backstrom, Sergei Fedorov and Alexander Semin scored the goals - one in each period - Huet made 30 saves, and league MVP candidate Alex Ovechkin made up for another frustrating offensive effort by depositing Jim Dowd headfirst into the Philadelphia bench for the highlight hip-check of the game.
Vaclav Prospal scored for the Flyers in the second period, and Derian Hatcher made things interesting when he scored with 4:43 remaining - less than one minute after Semin's power-play goal had given the Capitals a 3-1 lead.
The Flyers still have a 3-2 lead in the series and will have another chance to clinch in Game 6 at home on Monday.
The Capitals, in the playoffs for the first time since 2003 with a build-from-the-ground-up team, showed their playoff inexperience when were dominated in the first three games of the series. They stole Game 1 with a third-period comeback, but their best game before Saturday was the double-overtime loss in Thursday's Game 4, when they started to match the physical play of the Flyers.
They kept it up Saturday, committing two roughing penalties in the first minute and outhitting the latest version of the Broad Street Bullies 22-9 in the first period. The Flyers were outshot 12-4 in the period and didn't put a puck on goal in the final 15 minutes.
For the first time in the series, the Capitals held the lead after the opening 20 minutes. They went up 1-0 after Ovechkin, bearing down on the crease, drew a hooking penalty on Kimmo Timonen during a power play to give Washington a two-man advantage. Backstrom converted the 5-on-3 by waiting on the doorstep to deposit Semin's cross-ice pass.
Although there was only one goal, the first period was a nonstop eyeful of up-and-down hockey, although the scoring chances heavily weighted in the Capitals favor. Semin hit the right post late in the period, while Huet stopped Danny Briere's on a mini-breakaway to thwart Philadelphia's best threat.
Fedorov gave the Capitals a 2-0 lead early in the second with a backhander on a feed from Viktor Kozlov, who worked hard to win the puck in the corner.
The Flyers came to life later in the second when Fedorov's holding penalty gave Philadelphia a 5-on-3 power play. Prospal scored his third goal of the series on the final second of the two-man advantage.
The goal energized the Flyers, who played the stronger and better over the second half of the game. They again stymied Ovechkin, holding him without a point, but they gave the Capitals too many power-play chances and couldn't solve Huet until it was too late.
With Scott Hartnell in the penalty box for hooking, Semin's power-play goal gave the Capitals a 3-1 lead with 5:27 remaining. Hatcher quickly made it a one-goal game, but the Flyers couldn't get the game-tying score. They ended up outshooting Washington 32-26 for the game.
Notes: The Capitals are trying to rally from 3-1 down to win a series for the second time in franchise history. The only other time it happened was 20 years ago - against the Flyers. ... Martin Biron made 23 saves for the Flyers.
