Making his debut for the Korean team after joining last month, Mikkelsen ended a captivating day with a 1.4sec advantage in his i20 World Rally Car over WRC leader Sébastien Ogier.
The lead battle was incredibly tight and three drivers topped the leaderboard over the six mixed surface speed tests covering 115.90km.
Sunshine and high temperatures ensured the dry gravel tracks west of Salou favoured the late starters. Those early in the order swept loose gravel aside to leave a cleaner and faster line for those behind.
The cleaning was not as pronounced as expected this morning and Ott Tänak led initially. Mikkelsen’s choice of hard compound tyres helped him move into a slender 0.6sec advantage over fellow Norwegian Mads Østberg at the midpoint.
Østberg edged ahead before Mikkelsen regained the initiative and held off a charging Ogier, despite a final stage glitch.
“I’m very happy with how it’s going. It’s a new car for me and I need to get used to it. I was too careful in the first two stages but I changed the differential settings and it gave me a better feeling. Something happened with the suspension in the last stage but we managed,” he said.
Road opener Ogier endured the worst of the loose gravel but was sublime in the technical asphalt midway through the long Terra Alta test which closed each loop. He masterfully managed his Ford Fiesta’s tired tyres to climb to second.
Kris Meeke won two stages in his Citroën C3 en route to third, 3.0sec off the lead. It could have been even better had the Briton not dropped vital seconds when he spun.
Tänak’s tenure at the front ended with a slow puncture and the Estonian was uncomfortable with his Fiesta’s handling this afternoon. He ended 3.3sec behind Meeke and 0.8sec ahead of a frustrated Østberg.
A hole allowed the cockpit in Østberg’s Fiesta to fill with dust and his temper reached boiling point when the heater jammed on in the final stage. Having never been outside the top two, he slipped to fifth.
Dani Sordo struggled for grip initially but the Spanish hero’s mood improved alongside the traction and he was 10.8sec off the lead in sixth, a place ahead of dispirited team-mate Thierry Neuville.
The Belgian’s title hopes were jolted when his choice of soft tyres were unsuited to the morning conditions and he grappled to find the ideal set-up when the stages were repeated.
Saturday features two identical loops of three tests, split by service, before ending with a crowd-pleasing stage along Salou seafront. It adds up to 121.86km of action.