Maxime Talbot, Matt Read and Claude Giroux also scored for the Flyers, who moved within two points of the idle New York Rangers and New York Islanders for the final playoff spot in the Eastern Conference.
The Capitals are a point ahead of Philadelphia in a jumbled East.
Desperate to get a point, the Flyers tied it at 4 when Timonen ripped a slap shot past Braden Holtby after several chances in front. Timonen then set up Fedotenko with a perfect crossing pass in OT to cap off a remarkable comeback and set off a wild celebration.
Marcus Johansson and Alex Ovechkin scored power-play goals 26 seconds apart in the third period to give the Capitals a 4-2 lead.
BLACKHAWKS 7, RED WINGS 1
DETROIT (AP) — Brandon Saad had two goals and an assist and Dave Bolland scored twice in the Chicago Blackhawks' win over the Detroit Red Wings.
Jonathan Toews added a goal and two assists and Jeremy Morin and Nick Leddy, also scored for Chicago. Cory Crawford made 33 saves.
Cory Emmerton scored Detroit's goal. Jimmy Howard was pulled in favour of Jonas Gustavsson early in the second period. Gustavsson made nine saves.
Chicago led 3-0 at the end of the first period after scoring on its first three shots in a 1:39 span in the game's first 4 1/2 minutes.
BLUE JACKETS 2, DUCKS 1, OT
COLUMBUS, Ohio (AP) — Mark Letestu set up the only goal in regulation and scored the game-winner in overtime, and Sergei Bobrovsky stopped 29 of 30 shots to lead the Columbus Blue Jackets over the Anaheim Ducks.
The victory improved the Blue Jackets to 9-0-3 in their last 12 games at Nationwide Arena and gave them points in 15 of their last 17 games (10-2-5) to crawl into playoff contention in the West.
Emerson Etem had the only goal for the Pacific Division-leading Ducks, who had lost four in a row until winning 2-1 in Chicago on Friday night.
KINGS 3, STARS 2
DALLAS (AP) — Brad Richardson and Justin Williams scored third-period goals just over a minute apart to help lift the Los Angeles Kings past the Dallas Stars.
Jeff Carter also scored his 20th goal of the season for Los Angeles, which has lost just once in regulation in Dallas in its last 14 visits (11-1-2) and outshot the Stars 40-15.
Richardson's goal was particularly impressive, since the fourth-liner was playing his first game since Feb. 10 and third of the season overall after sitting out as a healthy scratch the other 32 contests. Jonathan Bernier needed to make just 15 saves for the Kings, and remained unbeaten — 8-0-0 in his starts this season.
Jamie Benn and Ray Whitney scored for Dallas, which had won both previous meetings between the Pacific Division rivals this season by a combined score of 7-2.
BRUINS 2, SABRES 0
BUFFALO, N.Y. (AP) — David Krejci and Nathan Horton scored goals less than three minutes apart in the third period, and Anton Khudobin stopped 26 shots in leading the Boston Bruins over the Buffalo Sabres.
Krejci broke open a scoreless game during a scramble in front with 7:06 remaining, and after Horton was stopped twice from in close by Buffalo goalie Ryan Miller. Krejci then returned the favour by setting up Horton for a tap-in in front with 4:16 left in helping Boston win for only the third time in eight games (3-4-1).
Khubodin earned the second shutout of his career, while the Bruins improved to 2-5 in their last seven road games.