Knuble enjoyed another solid season in 2003–04, 21 goals and 25 assists in 82 games with the Bruins. During which, he set the NHL record for the fastest two goals to start a game by one player on February 14 against the Florida Panthers. He scored a goal ten seconds into the first period and followed it up with another just 27 seconds into the game. After the season, Knuble signed a three-year contract with the Philadelphia Flyers in the off-season. He then played for Linköpings HC of the Swedish Elitserien during the 2004–05 NHL lockout, scoring 26 goals and assisting on 13 others in 49 games.