Mexico's monster 80km stage demands respect say WRC drivers
Crews braced for longest WRC stage for 30 years
The Norwegian completed seven passes through the 5.55km Llano Grande stage near the rally base of León, setting fastest time on his final run in a Volkswagen Polo R.
He was 1.6sec quicker than Thierry Neuville's Hyundai i20, with Sébastien Ogier, preparing to start his 100th WRC event, a further tenth of a second back in another Polo R.
"We had a good test in Almeria in Spain before coming here. We did a lot of runs to get a good feeling and the feeling is there," said Mikkelsen, who finished third in Mexico last year and used the shakedown to acclimatise to the power-sapping altitude in the mountains.
"We made some ride height changes but nothing major. The car feels great and I made a lot of runs to get used to the power here. Because of the altitude I need to be in different gears than normal, so I just drove several runs to get used to that," he added.
Jari-Matti Latvala and Dani Sordo were tied in fourth, 4.2sec off Mikkelsen's pace. Sordo's second run was interrupted when a steering rod broke on his i20 and the Spaniard spent more than 30 minutes in the test repairing it before returning to service. Hyundai colleague Hayden Paddon completed the top six.
M-Sport's Eric Camilli was 10th fastest, despite returning to service following an electrical problem on the liaison section after his first pass.