Mikkelsen wins Rally Australia
The Norwegian won the final round of the 2016 season by 14.9sec from team-mate Sébastien Ogier, who spun away his own chances.
It provided a perfect farewell for the German manufacturer, which bows out of the series after a dominant four-year period.
Mikkelsen's win in a Polo R was not enough to secure the runners-up spot in the drivers' championship.
Third place for Thierry Neuville in a Hyundai i20, a further 57.7sec back, secured the position behind the already-crowned Ogier.
Ogier won the final live TV Power Stage to claim three bonus points.
Neuville took two points for second, while team-mate Dani Sordo secured the final point.