As the only driver to take a set of medium compound tyres, one grade softer than the rest of the field on hards, Mikkelsen used his grip advantage to go 2.5 seconds faster than Citroen's Craig Breen in second.
Ogier half-spun into the plastic barriers lining the stage when the rear of his Ford Fiesta kicked up over a jump, leaving him unable to slow down in time for the following corner. His mistake cost him 7.5s relative to Mikkelsen.
Turkey Rally
Tanak: Turkey a low-point despite victory
18/09/2018 AT 17:09
Behind third fastest Ott Tanak, championship leader Thierry Neuville tied for the fourth quickest time with WRC2 support category driver Kajetan Kajetanowicz, both 3.1s behind Mikkelsen.
Three-time European champion Kajetanowicz was joined in the top six by Skoda factory driver Jan Kopecky.
The WRC2 performance evoked memories of Kopecky's outright stage-winning performance last year.
Toyota's Esapekka Lappi is seventh, with Mads Ostberg eighth and the third Toyota of Jari-Matti Latvala in ninth.
M-Sport suffered an especially poor stage. Before Ogier's mistake put him well outside the top 10, his team-mates Elfyn Evans could only muster the 10th fastest time.
Teemu Suninen in the third M-Sport failed to make the top 10, going slower than Kopecky's WRC2 team-mate Pontus Tidemand.
An untidy run by Hayden Paddon put him even further out of the top 10 than Ogier, twice overshooting the entry to roundabouts to finish 9.6s off team-mate Mikkelsen's time.
Turkey Rally
Ogier can't understand 'silly' Turkey crash
17/09/2018 AT 16:39
Turkey Rally
Tanak boosts WRC title hopes with Turkey win
17/09/2018 AT 09:29