OTTAWA, Ontario -- There are no easy games when a team's lineup is this diluted.
There are no guaranteed victories; no opponent that can be taken lightly.
Nonetheless, there are teams that the Penguins, even in their weakened state, have to feel they should beat.
That they must beat.
- Matchup: Buffalo Sabres at Penguins, 7:08 p.m. today, Consol Energy Center.
- TV, radio: Root Sports, WXDX-FM (105.9).
- Probable goaltenders: Marc-Andre Fleury for Penguins. Ryan Miller for Sabres.
- Penguins: Have lost past two home games in regulation. ... Fleury is seeking his 200th career victory. ... Are 2-1-1 in second game when playing on consecutive days.
- Sabres: Are 8-3 on road, including 3-2 win against Penguins Oct. 15 ... High-scoring LW Thomas Vanek has just seven goals, five assists in 23 career games against Penguins. ... Victory against Penguins is their only one against an Atlantic Division opponent (1-4-1).
- Hidden stat: D Paul Martin has not scored a goal on home ice since joining Penguins.
Teams such as Ottawa, bobbing along near .500 and far from certain of qualifying for the Eastern Conference playoffs.
But, ordinary as the Senators might be, containing them was more than the Penguins were capable of Friday night, as Ottawa put together a 6-4 victory at Scotiabank Place.
"That was a big game for us," defenseman Matt Niskanen said. "We approached it like it was an important one for us.
"I think everyone was focused, but we were lacking some details in our game. It doesn't really matter who's in the lineup. That's the attitude we're taking.
"We have to find a way to execute those details."
The loss was the Penguins' fourth in their past five games and dropped their record to 17-11-4. Ottawa, improved to 15-14-4.
The Senators got quality performances from top-shelf talents like Jason Spezza and Erik Karlsson, but the Penguins contributed to Ottawa's offensive rampage by playing loose in their own zone and giving the puck away far too often.
That led to them having to play from behind for most of the final two periods, and to have to try to survive what developed into a shootout.
"We don't ever want to have to try to win a game 7-6 or 8-7," left winger Chris Kunitz said.
Allowing the two points to slip away would have been troubling enough for the Penguins, but that might not even have been their most significant loss of the evening.
That is because defenseman Paul Martin left the game in the third period with an apparent leg injury after taking a hit from Ottawa defenseman Chris Phillips.
Coach Dan Bylsma said, "I don't have any idea" about the severity of Martin's problem. If it turns out that he has a lost-time injury, however, an already stripped-down defense corps will have to get by with yet another replacement from the American Hockey League.
Assuming there is one left there.
The Penguins played without center Jordan Staal for the second time in the past three games because of an unspecified injury and defenseman Zbynek Michalek, who missed his eighth because of a concussion.
The Penguins also had their usual absentee list headlined by center Sidney Crosby and defenseman Kris Letang, both of whom have either a concussion or symptoms associated with one.
Ottawa, however, was hardly at full strength.
Winger Milan Michalek, who began the night tied for the NHL lead in goals (19), missed his second game in a row and defenseman Sergei Gonchar, a Penguins alum, was held out of his fourth consecutive game because of an unspecified injury.
Colin Greening gave Ottawa a 1-0 lead 25 seconds into the second period when he drove to the net and steered a Spezza pass behind Penguins goalie Brent Johnson.
Just 71 seconds later, Steve Sullivan pulled the Penguins even as he got a pass from Arron Asham and beat Senators goalie Alex Auld from the inner edge of the right circle for his sixth goal.
The Penguins barely had finished celebrating Sullivan's goal, when Spezza put the Senators back in front, 2-1, by driving a shot past Johnson from the slot at 2:04.
After Daniel Alfredsson padded the Senators' lead at 6:45 by beating Johnson from inside the right circle, the Penguins countered with two, quick-strike power-play goals.
Niskanen scored on a slap shot from the left point at 11:07, just seven seconds after Chris Neil of Ottawa was penalized for hooking, and Evgeni Malkin scored at 12:14, eight seconds after Alfredsson was sent off.
Just 66 seconds later, Ottawa defenseman Jared Cowen threw the puck toward the net from the left side. It hit the skate of Penguins defenseman Brooks Orpik and caromed past Johnson.
"I don't know if that was the back-breaker because we were still in the game," Niskanen said.
"But it sure took away a lot of momentum."
Zenon Konopka gave Ottawa some insurance by scoring with 5.7 seconds left in the period, and Spezza beat Marc-Andre Fleury, who replaced Johnson at the second intermission, at 12:23 of the third. A Kunitz goal at 18:58 changed nothing but the Senators' margin of victory.
So Ottawa got a victory, and the Penguins got a lot to think about. Again.
"Bad breaks or not," Niskanen said, "we have to find a way to be better."
Dave Molinari: Dmolinari@Post-Gazette.com or Twitter @MolinariPG. First Published December 17, 2011 5:00 AM