Sami Kapanen scored the first of his two goals during Philadelphia's first-period barrage, which drove Giguere to the bench with 3:34 left in the period. Giguere entered the game 10-0-4 with a 1.98 goals-against average and had allowed only four goals on 77 shots over his previous four games.
Mike Knuble, Simon Gagne and Geoff Sanderson each had a goal and an assist for the Flyers, who came in with an NHL-worst 3-12-2 record. But they handed the Western Conference leaders their first regulation loss at home despite getting outshot 41-16.
Alexandre Picard had a power-play goal in the third, one of three by the Flyers with the man advantage.
The Flyers have had three other six-game losing streaks, most recently Jan. 25-Feb. 5, 1994. They are 3-6-1 since John Stevens replaced Ken Hitchcock as coach on Oct. 22.
Andy McDonald and Dustin Penner had power-play goals for the Ducks, who have lost two of three since setting an NHL record with points in their first 16 games. Chris Kunitz and Samuel Pahlsson also scored for Anaheim against Robert Esche, who made 37 saves.
Forsberg missed Philadelphia's previous two games because he was at a Cleveland orthopedic clinic getting fitted for a special brace designed to hold his right foot properly in his skate boot.
The five-time all-star had trouble the past two seasons finding one that fit well because of a congenital defect that caused his feet to turn inward and stretch the ligaments in his right ankle. He had offseason surgery.
Sanderson snapped a 1-1 tie at 11:16 of the first, scoring into an open net after Giguere stopped R.J. Umberger's 20-foot snap shot and Triston Grant hit the crossbar on the rebound. Forsberg added his sixth goal less than two minutes later.
The Ducks, who weren't short-handed during Sunday's 3-2 win over Minnesota, surrendered power-play goals 74 seconds apart by Knuble and Gagne as the Flyers increased the margin to 5-1.
Knuble, playing his second game after sitting out six with a broken finger, finished off a perfect passing play with Gagne and Joni Pitkanen. Gagne scored on a one-timer, forcing Anaheim coach Randy Carlyle to replace Giguere with Ilya Bryzgalov.
The Flyers, who had not scored more than four goals in any of their previous 17 games this season, took the lead at 1:48 when Kapanen scored.
Notes: The teams met for the first time since Nov. 22, 2003, in Anaheim. ... LW Kyle Calder and C Mike Richards have yet to score a goal despite playing in each of the Flyers' first 18 games. Calder, who had 26 with Chicago last season, was scratched for the first time since the Flyers obtained him from the Blackhawks for C Michal Handzus. ... The Flyers had their biggest offensive output since beating Washington 8-1 on Nov. 3, 2005.