Miettinen broke a 1-1 tie with 7:36 remaining in regulation as the Jets earned a 2-1 victory against the Buffalo Sabres at First Niagara Center.
Winnipeg is currently on a 6-0-1 run and Monday's win sets up a game against the Washington Capitals on Tuesday that will have major playoff implications. The Jets are already eagerly looking ahead.
"I think it's been circled on our calendar for a long time now," Jets captain Andrew Ladd said. "We wanted to put ourselves in a position where [Tuesday's] going to be a meaningful game and we've done that. So here it is."
With two games remaining, Winnipeg sits in ninth place with 51 points, one back of the seventh-place New York Rangers, the eighth-place Ottawa Senators and the No. 3 seed, the Southeast Division-leading Capitals. The Jets are also two-points behind the sixth-place New York Islanders. None of those teams have clinched a playoff berth yet.
Washington can clinch the Southeast on Tuesday with a win in regulation or overtime. Winnipeg is 1-3-0 against the Capitals this season. Washington outscored the Jets 10-1 in the past two games, which were played on back-to-back nights in Winnipeg.
"For us, we know what's at stake. It's the time of the year that you put your best foot forward. They'll be coming, they'll be coming for sure," Jets coach Claude Noel said. "They'll know exactly what we're doing and we're going to have to put our best foot forward. We know what we did last time we played them in our building and they'll be all we can handle. We've got to give 'em our best."
The Jets entered the game coming off a six-game homestand in which they went 5-0-1. That run helped put them back in the playoff picture as their victory against the Sabres improved their record to 24-19-3.
"This game means nothing now," Jets forward Evander Kane said. "We needed this game in order to make something of [Tuesday]. [Tuesday's] the biggest game of our season."
Aaron Gagnon also scored for Winnipeg, while Ondrej Pavelec made 24 saves in his 11th straight start. His best stop of the night came with 5:45 left in regulation, when he robbed Thomas Vanek with a glove save.
"[Vanek] was waiting, he was holding the puck. And it just hit my glove. I don't know what to say," Pavelec said with a smile. "I think the guys deserved my help because they played really well all game and that's our job, to make a save. I was happy that I was able to do it."
Pavelec and the Jets defense also prevented Buffalo's steadiest pressure of the night, which came with under a minute to go and the extra skater on.
Goaltender Jhonas Enroth kept Buffalo in the game, turning aside 37 shots. Vanek, Buffalo's leading scorer, tallied for the Sabres.
"[Enroth] was great. He was our best player by far," Sabres forward Steve Ott said. "He came in and we knew he'd be strong."
The Sabres (19-21-6) were eliminated from playoff contention with a loss to the New York Rangers on Friday.
For the game winner, Miettinen accepted a pass from James Wright at the right point and took a slap shot that made its way under Enroth's left arm and trickled in over the goal line. Miettinen said he didn't even see it go in.
"No, I really didn't see how it got in there. I was just listening to the crowd," Miettinen said.
Gagnon opened the scoring 7:42 into the second period. Jets defenseman Derek Meech skated in down the left wing boards and threw a pass in front of the net just in front of the red line. Gagnon deflected the puck up over Enroth's left shoulder as three Sabres watched. The goal was Gagnon's third goal of the season and Meech's first point of the 2012-13 campaign.
Vanek tied the game with 8:03 to play in the second with his ninth power-play goal of the season. Drew Stafford crept in from the left point and swung a pass cross-ice to Tyler Ennis. Ennis put the puck toward the net and Vanek deflected it top shelf for his team-leading 18th goal.
With his goal, Vanek passed Mike Foligno for the sixth-most goals in Sabres' history with 248. Vanek is four behind Craig Ramsay for fifth place.
Kane was awarded a penalty shot with 5:01 to play in the first period after Sabres defenseman Andrej Sekera dived and interfered with Kane on his way to the net. Enroth made a glove save on the penalty shot attempt that deflected up and over the net. Enroth is now 1-for-2 in his career on penalty shots, while Kane is 1-for-5 in his career.
The penalty shot was one of 15 saves Enroth made in the first period to keep the game scoreless as the Jets outshot the Sabres 15-4. Enroth had made 29 saves in the game by the time the second period wrapped up.
Enroth capped off an acrobatic sequence late in the second period by stopping Jets captain Andrew Ladd with the back of his skate while facing the mouth of the net. After a shot went off the post, Enroth was scrambling on his back outside of the crease without a stick. The puck made its way to the front of the net and Enroth stopped lad with his back turned to the play. He stopped another shot by Gagnon before Buffalo was able to clear the zone.
Jets forward Kyle Wellwood left the game in the second period after blocking a shot from Vanek. Noel said that Wellwood will be out long term with an injured hand.
"Our team has showed a lot of things for me. Character, a lot of resiliency, our focus has been really good," Noel said. "Our work ethic and our 60-minute game have been way better. I think it's been driven from intensity, emotion and we know what's at stake."