Geoff Courtnall added two goals as the Capitals won their first season opener since 1982. They snapped an 0-5-1 stretch in openers with three power-play goals and a 44-24 shot advantage over the team that eliminated them in the first round of the playoffs last spring.
Washington trailed, 1-0, 2-1 and 3-2, before tying the score at 3-3 when Hunter shot a pass from Scott Stevens past Philadelphia goalie Ken Wregget with 11:18 left in the second period.
Washington took a 4-3 lead, Ridley scoring with 10:11 left.
Courtnall scored his second goal with 4:44 left to give Washington its 5-3 advantage.
Philadelphia (0-2) took one-goal leads on goals by Tim Kerr, Murray Craven and Mike Bullard.
New York Rangers 4, Winnipeg 1--John Ogrodnick scored two goals as the Rangers opened their season with a win at Winnipeg, Canada.
Kelly Kisio and Darren Turcotte also scored for the Rangers, who continued their hot streak after winning six of their last seven exhibition games.
Pat Elynuik scored Winnipeg's goal in the first period.
John Vanbiesbrouck blocked 34 shots for the Rangers, including pad saves on Brian McReynolds and Paul Fenton from the crease.