WASHINGTON -- Third periods against the Washington Capitals continue to be unkind to the Pittsburgh Penguins.
 
The Penguins lost to their rivals for the third time in as many tries this season, and what transpired shortly after the second intermission was again their undoing in a 4-3 shootout defeat on Wednesday night.
 
"The frustrating part is you make the same mistakes over and over again and you don't learn from them," defenseman Brooks Orpik said. "That's the frustrating part. It's not like we're getting behind, we're blowing leads."
 
Pittsburgh has not trailed heading into the final 20 minutes of regulation in any of its three meetings with Washington this season. The Penguins carried a 2-1 advantage into the final period Wednesday, but two goals in span less than two minutes left them scrambling for the equalizer.
 
Alexander Semin scored a shorthanded goal at 5:36 when he carried the puck into the zone and whipped a shot past Marc-Andre Fleury's left shoulder. Eric Fehr pushed Washington in front at 7:32 when he directed Mike Green's slap shot past the Pittsburgh goaltender.
 
"We get a power play in the third period, we're up by a goal -- even before the Semin goal it was as sloppy there," Orpik said. "It looked like we lost our focus there for whatever reason. It's frustrating.
 
Added defenseman Alex Goligoski, who unsuccessfully tried to mark Semin as he darted toward the middle of the ice: "Obviously you can't give those [shorthanded] goals up. That was a big goal for them and it took a little out of us. I mean, we had the lead going into the third there and that's a goal we can't give up."
 

While the Penguins were able to pull even before losing in a shootout, this is not the first time they've had third-period problems against the Capitals. The last time these two teams met at the Verizon Center, Pittsburgh led 4-2 after two periods before a pair of Alex Ovechkin goals sent the game to overtime. Mike Knuble, whose shootout goal won Wednesday's game, got the winner that day in OT.
 
The teams were tied 3-3 after two in first clash of the season at Mellon Arena before the Capitals poured in three consecutive goals.
 
"I don't know," defenseman Kris Letang said when asked why the defending Stanley Cup champs can't close out the Caps. "We try to shut down those powerful forwards like Ovechkin, Backstrom and Semin by playing them really tight. We keep giving up the lead in the third there and it is really tough to come back against such a powerful skilled team like that."
 
This trend reaches back to last season as well. Not only are the Capitals 6-0-1 against the Penguins in the regular season since the start of 2008-09, they've outscored them 16-2 in the third periods of those games.
 
"I don't know [why]," forward Bill Guerin said. "I guess if we had the answer, we wouldn't be in that situation. I don't have an answer."
 
Pittsburgh's inability to hold leads against Washington even extended to the shootout on this night. Goals by Letang and Sidney Crosby gave the Penguins a 2-0 advantage in the one-on-one format by tallies by Ovechkin, Semin and Knuble completed the comeback.
 
"As a goalie, they were good plays, but when you're down 2-0 in a shootout usually it doesn't look good," Capitals goaltender Jose Theodore said. "But we have so much skill that we didn't panic and came back and scored some goals. From there I knew if I could make a couple of saves we'd get the goal and that's what we did."