Ottawa produced the first three goals of the game and the last three as well in snapping a two-game losing streak. Tampa Bay had won four in a row.
Steven Stamkos scored his league-leading 48th of the year to cut the Tampa Bay deficit to one 5:41 into the final period.
Michalek then took over, giving Ottawa insurance with a power-play goal and finishing things off with a pair of empty-net tallies. He has 31 goals for the season.
Ben Bishop, called up to take over as Ottawa's backup goaltender, made his first start of the season and stopped 25 shots. It was his first NHL action since last season, when he was with St. Louis.