The Finn, driving a Skoda Fabia Rally2, started the day in second behind Emil Lindholm. However, an uncharacteristic mistake saw the early leader crash out on the Kaihuavaara test, handing the lead to Asunmaa.
The local man tussled for the top spot stage-by-stage with Volkswagen Polo pilot Egon Kaur, who picked up a 10sec time penalty for booking in late at a time control.
At close of play, Asunmaa’s advantage over his rival was just 12.5sec. With two stages still to run on Sunday, anything could happen.
Fabia man Eerik Pietarinen was 1min 5.5sec down on the leading pair in third. He held a miniscule 1.7sec advantage over fourth-placed Mikko Heikkilä, who was driving a similar car.
World Rallycross legend Mattias Ekström completed the top five, 1min 2.9sec further back in his Skoda. Ekström has enlisted the services of ex-Junior WRC champion Emil Bergkvist to read the pace notes this weekend.
Estonian star Gregor Jeets trailed the leaders by 5min 32.5sec at the end of the day in sixth. He held a 1min 58.6sec advantage over Pekka Keski-Kors, followed by Tuomas Skantz just 8.5sec behind. All three were driving Fabia cars.
Citroën man Michal Solowow and Saudi-Arabian Rakan Al-Rashed rounded out the top ten heading into the final leg.
- Full coverage from Arctic Rally Finland Powered by CapitalBox 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.