Matt Carkner scored at 7:06 of triple overtime as the Ottawa Senators fought back from the brink of elimination to force Game 6 in the Eastern Conference quarter-finals.

The rugged defenceman's goal appeared to go off a Pittsburgh player in a 4-3 result for the Senators, with the next game shifting to Ottawa on Hockey Night in Canada on Saturday (CBC, CBCSports.ca, 7 p.m. ET).

Ottawa trails the best-of-seven series 3-2.

The Senators won the longest game in franchise history thanks to an unlikely source. Carkner, 29, just finished his first full NHL season and scored twice in 81 games.

"Personally, it's been great," said Carkner. "Just being able to compete, let alone scoring an overtime game winner."

Peter Regin helped force extra time for the Senators with a third-period goal at Mellon Arena, while Jarkko Ruutu and Mike Fisher scored first period goals to put Ottawa up 2-0 before the Penguins countered.

'We'll take it'

Senators goalie Pascal Leclaire was valiant in his first start of the series, finishing with a franchise playoff record 56 saves.

"It was a great game and it was a lot of effort," Leclaire told HNIC. "It was a weird bounce at the end but we'll take it and we're excited we're able to come back [Saturday] at home."

Ottawa started and finished strongly, playing with grit. The Sens overcame a prolonged funk during the middle part of regulation, with Pittsburgh at one point accounting for 23 of 28 shots.

Sidney Crosby finished with a goal and an assist for Pittsburgh to push his NHL-leading playoff total to 13 points. Chris Kunitz scored a contentious goal late in the second, with Kris Letang getting the Penguins on the board.

"A lot happened [in overtime] with penalties and chances and posts, but that's just the way it works out," Crosby said. "Unfortunately, we didn't get it done here, but we've got to find a way to regroup and be ready to go to Ottawa."

Evgeni Malkin finished with a pair of assists, with goalie Marc-Andre Fleury making 40 saves.

The defending Stanley Cup champions are in familiar territory, having twice last year failed to close out 3-1 series leads on their first opportunity.

Penguins coach Dan Bylsma praised Ottawa's team commitment to defence.

"They did a remarkable job of making it difficult to get [shots] through, they blocked a lot of shots, we had some good very chances in overtime that their defencemen and players were blocking and their goaltender played very well tonight," said Bylsma.

Jason Spezza started the sequence on Ottawa's first goal midway through the first, working in the corner and dropping the puck to Erik Karlsson at the point. The Swedish defenceman's shot hit both Fisher and Pittsburgh defenceman Sergei Gonchar before sliding past Fleury.

The Senators went up by a pair just 68 seconds later later. Nick Foligno was behind the Pittsburgh net and banked a pass off Penguins defenceman Jay McKee, allowing Ruutu to poke the puck between Fleury's pads.

Bylsma called a timeout, but it didn't immediately help. Ottawa captain Daniel Alfredsson couldn't lift the puck over Fleury on a great chance to could have put the visitors up by three goals.

The Senators were back-checking well to prevent the type of scoring chances they allowed frequently in the previous two games. But the Penguins began buzzing late in the period, with Ruslan Fedotenko testing Leclaire.

Ottawa goalie Pascal Leclaire, seen battling with Pittsburgh star Evgeni Malkin, set a franchise record for playoff saves in a game. (Gene J. Puskar/Associated Press)

Chris Phillips would soon take a penalty, which was converted in just 14 seconds by the Penguins. Kris Letang fired a loose puck from the right circle that snuck under Leclaire's arm and into the net.

Leclaire was in goal despite little activity at the end of the regular season due to the struggles of Brian Elliott in the previous two playoff games.

"He played outstanding," said Senators coach Cory Clouston. "He was confident, comfortable, I thought he was very square and poised and boy, did he come through for us."

The Senators goalie rebounded with saves on Alex Goligoski and Malkin in what was a largely uneventful second period until two minutes to go.

Pittsburgh began buzzing, and the whistle appeared to blow while the puck was crossing the goal line and the Ottawa net was being jarred.

It was initially ruled on ice as a non-goal, but a video review overturned the call. Kunitz was credited with the goal, much to Ottawa coach Cory Clouston's chagrin.

While the moorings of the net were lifted on the play, the officials ruled the pegs were still in place, making it an allowable goal.

"I thought the guys did a real good job of just keeping their heads level, keeping their emotions in check and not letting it affect us," said Clouston of the two big calls that went Pittsburgh's way.

The Penguins outshot Ottawa 19-5 in the period.

Kunitz was not as lucky in the third. He knocked a puck in the net on a power play but with a high stick, and later with Leclaire at his mercy after Bill Guerin's initial shot saw the puck hop over his stick.

The Penguins went ahead at 9:01 of the third because of their two offensive superstars.

Malkin disrupted Ottawa puck carrier Karlsson and then drove to the net with a chance, with the rebound knocked in by Crosby while falling to the ice.

Ottawa didn't fold, winning a face-off just over one minute later in Pittsburgh's end and taking advantage of a turnover to lead to Regin's slapper from the middle of the ice to tie the game 3-3.

In the first overtime, Fleury was called upon to make big saves on Phillips and Chris Neil. Spezza took a shot that led to a juicy rebound, but Foligno's skate guided the puck into the net, officials ruled.

"I didn't really think it was a kicking motion, but fortunately it didn't cost us the game," said Clouston.

Leclaire kicked out an Alexei Ponikarovsky chance in a period in which both clubs took penalties but were able to kill them off.

Regin deked Fleury but couldn't tuck the puck inside the right post early in the second extra session, while Pittsburgh hit the post behind Leclaire.

The game was the 29th longest in NHL history. Pittsburgh played a game in 2000 that went into the fifth overtime period.

With files from The Associated Press