A thrilling battle unfolded in the premier support category with Mikkelsen drawing first blood in the Peipsiääre opener.
His early advantage was short-lived, however, when Toksport Škoda Fabia Rally2 team-mate Emil Lindholm moved ahead on the very next test and held the top spot for the rest of the morning.
The pair were split by just tenths of seconds throughout the afternoon until a front left puncture on the penultimate blast cost Lindholm almost one minute. That promoted his colleague back in front as Teemu Suninen inherited second overall just 1.7sec behind.
Heavy rain in the Vastsemõisa finale left conditions akin to an ice rink, but Mikkelsen saw it as an opportunity to make a move. He blitzed Suninen by 10.2sec over the treacherous 6.7km test, stretching his lead over the Hyundai i20 N Rally2 driver into double figures overnight.
Victory in Estonia would mean a lot to the Norwegian. His title defence is on the rocks after back-to-back retirements at the previous two rounds.
"It's been a very good day,” said Mikkelsen. “I think we have been driving cleverly, like in the previous rallies. We pushed when we felt comfortable and played it safe when the risk of punctures was high with the ruts.
“We have a nice lead for tomorrow now and hopefully we can have a good day. There's still a long way to go.”
Marco Bulacia filled the final podium spot and topped the WRC2 Junior standings in another Toksport Škoda but trailed the leaders by 37.7sec at close of play. He had 18.7sec in hand over Lindholm, who plummeted to fourth with the puncture.
Jari Huttunen only broke into the top three on one of the day’s eight superfast speed tests despite winning Thursday evening’s curtain-raiser in Tartu.
The M-Sport Ford driver brought his Fiesta Rally2 home 14.0sec behind Lindholm, with championship leader Kajetan Kajetanowicz rounding off the leaderboard in another Fabia car.
Egon Kaur stayed in touch with the podium battle despite his Volkswagen Polo shedding a front bumper on the second stage and losing downforce. Things turned sour later in the day when the home hero retired, picking up two punctures whilst only carrying one spare wheel.
Hyundai youngster Fabrizio Zaldivar nursed a broken driveshaft through the final loop and WRC returnee Hayden Paddon retired at the mid-leg service after returning a positive Covid-19 test. Also making an early exit was Bruno Bulacia, who retired his Fabia in the morning.
- Full coverage from Rally Estonia is available on WRC+ All Live here, including every stage broadcast as it happens as well as key interviews, features and expert analysis from the service park.
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