The Estonian driver pushed his Hyundai i20 N to its limits on superfast gravel stages clustered around the Jämsä region, maintaining his position at the head of the field with just four stages remaining.
Wet conditions early in the day weren’t quite to Tänak’s liking, although he arrived back to the mid-leg service in a slightly more comfortable position than when he had left first thing in the morning.
He was more confident on the drier, grippier second pass and set a similar pace with championship leader Kalle Rovanperä, who surged through the field to end the day just 8.6sec in arrears.
The competition in Finland is traditionally very tight and, with Sunday’s itinerary adding up to just 43.92km, Rovanperä would need to be on another level to realistically overturn the leader. That said, he’s carried out similar feats already this year…
"It's still a bit of a surprise to be where we are at the moment, but definitely it's been a good day considering the conditions that we had,” reflected Tänak. “We really thought we would lose a lot more time and actually we are doing good."
Rovanperä was the driver of the day, taking out five stage wins in his GR Yaris machine.
He was hampered by loose road-opening conditions on Friday which left him down in fourth overall, but the Finn blitzed Toyota team-mates Elfyn Evans and Esapekka Lappi to climb the order.
“We lost quite a lot of time yesterday, but today we have been trying our best to catch it,” he said. “It's not easy because the gaps are so small, but we have good points coming and tomorrow we just need to finish the job."
Lappi was feeling frustrated after his car scooped up a stray rock on SS16 which cracked the windscreen, drastically reducing visibility. He had to err on the side of caution over countless blind crests and trailed Rovanperä by 26.8sec to fill the final podium spot.
Evans, too, was in trouble. His Yaris took a heavy compression on the penultimate stage which damaged the rear left upright and suspension strut.
Frantic repairs were made using ratchet straps and cable ties and the Welshman nursed the car through Vekkula 2, dropping almost one minute while amazingly still holding his position in fourth overall.
Thierry Neuville’s Hyundai squad fitted new differentials to the car overnight and he enjoyed a drama-free day. The Belgian was a lonely fifth overall - 45.8sec behind Evans but with 42.0sec in hand over Toyota youngster Takamoto Katsuta, who threw away time with a series of spins.
M-Sport Ford duo Gus Greensmith and Pierre-Louis Loubet were in a battle of their own for seventh overall, with Loubet setting the early pace before being overtaken by his Puma colleague on SS17. The pair will start the final leg just 4.2sec apart, while Teemu Suninen and Emil Lindholm rounded off the leaderboard in WRC2-specification cars.
VIDEO: Breen hits rock in SS12
Craig Breen was the day’s only frontrunning casualty and retired from fifth overall in the second stage. The Irishman misjudged his line over a high-speed jump, colliding with a rock which ripped a rear wheel from his Puma.
Sunday’s finale has been tweaked from last year, with Oittila’s (10.84km) flowing roads and Ruuhimäki’s (11.12km) big jumps taking centre stage. Ruuhimäki’s second pass forms the bonus-points paying Wolf Power Stage.
- Full coverage from Secto Rally Finland 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.