The Penguins had an eight-game winning streak snapped, falling for the first time since Jan. 11 in a game against Washington that also ended 1-0.
Reimer shared time with Jonas Gustavsson early in the season, but had only one appearance in January. His return to action turned into his second shutout of the season and the fifth of his two-year career.
The only goal of the game came with 6:05 left in the third period from Clarke MacArthur, his 16th of the season.
Brent Johnson made 22 saves for the Penguins. During their streak of eight straight wins the Penguins average 4.1 goals per contest.