Toskala, before giving up a late third-period goal to Andrei Zyuzin, had gone more than 119 minutes without allowing a pre-season goal. He shut out Vancouver on Tuesday and seems to have secured the starting goalie role in his battle with Evgeni Nabokov.
Patrick Marleau, Mark Bell and Joe Thornton added goals as the Sharks (6-2-0) finished winning five of their final six games.
Jamie McLennan and Brent Krahn combined to record 28 saves on 33 shots as the Flames (3-3-1) closed out their pre-season with three straight losses.
Michalek took the NHL lead when he scored his sixth goal of the pre-season, taking a pass from right wing Steve Bernier and tapping the puck past McLennan with 1:14 left in the first period. He added his seventh goal of the pre-season and second of the game midway through the third period.
The Sharks made it 2-0 when Patrick Marleau scored his third goal of the pre-season after grabbing a rebound and catching McLennan leaning the wrong way.
Bell, the Sharks' top off-season acquisition, ran the score to 3-0 when he scored his first goal of the pre-season in the third. It landed behind Krahn in the upper left corner of the net.
Thornton, the league's reigning MVP, scored on a 5-on-3 power play when he caught his own rebound and tipped it past Krahn.
Calgary gave starting goalie Miikka Kiprusoff the night off.
Sharks defenceman Christian Ehrhoff left the game midway through the second period with upper body soreness and was listed as day-to-day.