The two teams played each other twice in the last month of the regular season, splitting the matchups with one win each. There were many intense moments, such as an all-out brawl that had Flyers coach Peter Laviolette getting caught up in a shouting match with Penguins assistant coach Tony Granato.
However, the regular season is now in the books, and the playoffs are a fresh start. The Penguins will be eager to forget that the Flyers dominated them in the regular season, while the Flyers will be looking to prove that they can get past their biggest rivals in the first round.
Both teams have several highly-talented players worth keeping an eye on, and here are some of the best individual player matchups to watch.
Evgeni Malkin is having a bounce-back season after spending much of 2010 and 2011 on the injured list. The 2009 Conn Smythe Trophy winner finished the regular season first in the NHL with 109 points and second in the NHL with 50 goals. Over 75 games, that gives him an average of 1.45 points per game.
Malkin also has 73 points in 62 playoff games, including a career-high 36 points in 24 games in 2009, when the Penguins captured their third Stanley Cup.
Claude Giroux finished the 2011-12 season second in the NHL with 65 assists and third with 93 points, averaging 1.20 points per game. He also had a career-high 28 goals this season.
In the playoffs, he has 38 points in 40 games.
Advantage: Malkin, but Giroux has already shown he can be a strong postseason contributor with the Flyers. Don't count him out.
James Neal had his first taste of postseason hockey last year, when he was traded to Pittsburgh from the Dallas Stars. He had two points in seven games, as the Penguins dropped a 3-1 series lead to the Tampa Bay Lightning in the Eastern Conference Quarterfinals.
This season, Neal is having a career year, as he finished fourth in the NHL with 40 goals and seventh with 81 points. He was also first with 18 power-play goals.
Scott Hartnell, meanwhile, was second in the NHL with 16 power-play goals. He also finished sixth in the league with 37 goals and had 67 points on the season. He was first on the Flyers in goals scored.
Both Hartnell and Neal were named to the NHL All-Star Game for the first time in their careers.
This is an interesting matchup because both players are contributors to their teams' power plays, which are ranked fifth and sixth in the NHL with 19.7 percent success rates. However, Philadelphia has more power-play goals scored, with 66. Pittsburgh has 57 power-play goals.
Advantage: Hartnell, by virtue of the fact that he brings more postseason experience, including a Stanley Cup Finals appearance in 2010.
This matchup of defensemen pits a battle-tested Kimmo Timonen against a young blueliner in Kris Letang, who is establishing himself as one of the NHL's best.
This year, Letang led Penguins defensemen with 42 points despite missing 31 games due to injuries. This is the second 40-point season of his career, as he had 50 points in 2010-11. He also led the Pens with 24:50 of ice time per game.
In the playoffs, Letang was part of the Penguins team that won the 2009 Stanley Cup. He has 26 points in 50 playoff games in his career.
Timonen was in the 2010 Stanley Cup Finals with the Flyers and has 30 points in 69 postseason games. This is his fifth season with the Flyers, and in 2011-12, he led Philly defensemen with 43 points. He was also fifth with 21:14 of ice time per game.
Advantage: Small edge to Letang, who has a Stanley Cup under his belt. However, both are solid offensive defensemen who have the experience necessary to guide their teams' blue lines.
Marc-Andre Fleury, once thought to be lacking the ability to come up big in important games, has turned his reputation around, as the Penguins have become a contender. He now boasts a Stanley Cup (2009) and a career playoff record of 41-28 with five shutouts to go with a .910 save percentage and a 2.52 GAA.
This season, he finished second in the NHL with 42 wins while posting a .913 save percentage and 2.36 GAA, as well as three shutouts. It marked the second 40-win campaign of his career.
Ilya Bryzgalov struggled in the first of his nine-year deal with the Flyers, but managed to turn it around in the later part of the season. He finished with a 33-16-7 record with a .909 save percentage and 2.48 GAA. He was fifth in the NHL with six shutouts.
However, Bryzgalov has never won a playoff series as a starting goaltender. Although his playoff save percentage (.917) and GAA (2.55) are solid, he has a 12-13 record in the postseason with the Anaheim Ducks and Phoenix Coyotes.
Advantage: Fleury, for obvious reasons. Bryzgalov is a solid veteran netminder, but has yet to show he can help a team steal a playoff matchup.