Updated

The mighty Pittsburgh Penguins secured the East's top playoff seed in their last trip to the ice and they'll aim for a seventh straight win when they visit the Ottawa Senators on Monday.

Pittsburgh notched a 3-2 win Saturday in Boston to lock up the No. 1 spot in the conference playoffs. All Pittsburgh has left to play for in the regular season is the best record in the NHL, which currently belongs to the Chicago Blackhawks.

Chicago is five points ahead of the Pens for the Presidents' Trophy with four games left to play for both teams. Pittsburgh would be eliminated from the race if it loses Monday in regulation and the Blackhawks win their game in Vancouver.

Ottawa, meanwhile, is still battling for a playoff spot and enters Monday tied with the New York Rangers for the seventh spot in the East with 52 points each. The Senators also are just three points ahead of ninth-place Winnipeg, which plays Monday in Buffalo.

The Sens hold a game in hand over both the Jets and Rangers, who are idle on Monday.

Ottawa is 0-1-1 against the Penguins this season, as it dropped a home shootout decision to Pittsburgh on Jan. 27 before getting beat by a 4-2 score in a Feb. 13 meeting in the Steel City. The regulation loss in Pittsburgh was also the last game for Ottawa defenseman and reigning Norris Trophy winner Erik Karlsson, who suffered a severe laceration to his left Achilles when he got clipped by the skate of Pittsburgh's Matt Cooke.

Karlsson was cleared for contact on Friday and he could return to the lineup before the end of the regular season. Karlsson, who has six goals and four assists in 14 games this season, was originally expected to miss six months of action due to the cut, but he shocked everyone by resuming skating three weeks ago. Senators general manager Bryan Murray said Karlsson will be back in the lineup once he returns to game shape.

Ottawa had won four in a row before dropping Saturday's 4-1 decision to Toronto in the third test of a four-game homestand. James van Riemsdyk scored twice and James Reimer frustrated the Sens with 49 saves to help the Maple Leafs secure their first playoff berth since 2004.

Jakob Silfverberg netted the lone Ottawa goal, while Craig Anderson allowed all four goals on 22 shots for the Senators.

"We have four games left but to me it has been a sprint since January 19," Ottawa coach Paul MacLean said of his team's push toward the postseason. "If we come back and do this again Monday night (against Pittsburgh) we'll get a better result."

Ottawa, which will play two of its final three games of the regular season on the road, is 15-4-3 at Scotiabank Place this season.

Jussi Jokinen scored a goal and set up a pair of power-play tallies in the third period to lift the Penguins to Saturday's 3-2 victory over the Bruins at TD Garden. Jokinen has four goals and four assists in six games since being acquired at the trade deadline from Carolina.

The Bruins and Pens were set to play Friday night, but the game was postponed because of the day-long manhunt for the second Boston Marathon bomb suspect who was taken into custody Friday night. Pittsburgh was slated to play at home Saturday night against Buffalo, but that game was shifted to Tuesday.

Jarome Iginla and Kris Letang scored in the third period for the Penguins, who have won six in a row and 21 of their last 23 games. Tomas Vokoun made 38 saves in the victory.

Iginla has three goals in nine games with the Penguins since being acquired from Calgary in late March. He was booed every time he touched the puck, as the Bruins initially thought they had a deal with the Flames before he was shipped to Pittsburgh.

"I wasn't surprised," Iginla said of the crowd reaction. "It's a great sports city. At the time I was very humbled and flattered both teams were interested in me."

Pittsburgh is playing its second-to-last road game of the regular season tonight. The Pens have identical 17-5-0 records at home and on the road in 2013.

Letang is a game-time decision for tonight after missing practice on Sunday due to illness.

The Sens and Pens have split the last eight encounters in this series, but Ottawa has claimed four of the last six tilts at Scotiabank Place.