Michalek scored his second goal of the game and 10th of the season with 23 second left as Ottawa defeated the Buffalo Sabres 3-2 on Thursday.
"We believe there's still lots of goals left in Milan, but it's taken a long time to get them out this year," Senators coach Paul MacLean said. "With his work ethic and his play without the puck and his abilities on the penalty kill, there's never been a question about his contributions to the team.
"We knew if he would just stay with it good things would happen for him."
The Sabres had fought back to tie the game with two third-period goals, but Senators captain Jason Spezza found Michalek, who beat Jhonas Enroth over the shoulder for the winner.
"It's all about winning and we're not doing that right now," said Sabres defenceman Henrik Tallinder, who said the puck hit the referee and went right to Spezza on the winning goal.
"Nothing you can do about it. We didn't go the right way that maybe we should have, but it hit the ref and bounces are going to happen but they just weren't in our favour."
Erik Karlsson also scored for the Senators (26-21-11) while Craig Anderson made 30 saves.
Tyler Ennis and Drew Stafford scored for the Sabres (15-34-8), who lost for the fourth straight time. Enroth made 33 saves.
Following two periods that saw the Senators build a 1-0 lead, things opened up in the third period with four goals off several good scoring opportunities.
It started with Michalek doubling the Senators' lead to 2-0 just 10 seconds into the period on a perfect pass from Spezza which allowed Michalek to redirect the puck in.
The goal was the fastest in team history from the start of a period breaking the old record of 12 seconds set by Spezza back in 2009.
"At least I'm still involved in (the record) I guess. I would have shot it if I knew that," Spezza joked after the game, quickly getting serious when the Sabres comeback was brought up.
"A two goal lead is a tricky lead. We give up the one goal to make it 2-1 and then really anything can happen with a bounce here or a bounce there. Hopefully we learn from it."
Ottawa got into penalty trouble but was fortunate when Ennis hit the post on one power-play opportunity.
The Sabres also had a five-on three advantage for 17 seconds but were unable to get a shot on goal during that brief stretch.
Ennis broke Anderson's shutout bid at 10:25 of the third when the puck came to him in front off a failed wrap-around attempt by Stafford. The puck rolled off Stafford's stick right to Ennis who had an empty net to shoot at.
Stafford then tied the game at 15:46 when he grabbed a rebound and went around Anderson who was down and out on the play.
"There were no excuses not to battle as hard as we could going into that third period and we did a really good job," Ennis said. "It's super disappointing to lose that one."
Only seven goals, including one in a shootout, have been scored in the previous three matchups between the Sabres and Senators.
Karlsson put the Senators on the board first with his shot from along the boards eluded Enroth just 3:12 into the second period.
Neither team had many quality scoring chances despite seven power plays between them through the first two periods. But one scoring chance the Sabres did have though came late in the second when Stafford drove the Senators net from just above the goal line but he was unable to tip the puck through Anderson.
The Senators stymied the Sabres on all seven of their power-play opportunities.
"We've been winning faceoffs and doing a much better job up the ice and on the initial entry into our zone we've contested it and been hard to play against," MacLean said.
The Senators were 0-3 with the man advantage.
Notes: Forwards Linus Omark and Marcus Foligno along with defenceman Tyler Myers were scratches for the Sabres Thursday. Scratches for the Senators were defencemen Chris Phillips and Joe Corvo plus forward Matt Kassian….Senators forward Bobby Ryan has gone four consecutive games without a point, his longest such streak this season…The Senators are 10-0-3 in games this season when captain Jason Spezza has at least two points…Matt D'Agostini played his 300th NHL game Thursday night and his 25th with the Sabres…While the Senators have a game in Boston Saturday, the game Thursday was the last for the Sabres until after the Olympic break. The team will be off until Feb. 25 except for Ryan Miller (USA), Jonas Enroth (Sweden), Henrik Tallinder (Sweden) and Zemgus Girgensons (Latvia) who will all represent their countries at the Sochi Olympics. Sabres coach Ted Nolan will also be the head coach of Team Latvia.