The Toyota-driving Finn heads the order by a mere 1.0s from team-mate Sébastien Ogier on a day marked by five different stage winners, resulting in the top four crews being separated by just 5.4s.

Rovanperä initially languished in fifth overall after a lacklustre opener but posted top-three times in the remaining seven tests, confidently climbing the standings despite reporting excessive understeer in his GR Yaris.

He seized the lead after overtaking early pacesetter Takamoto Katsuta on this afternoon's second test at Lousã and went fastest on the penultimate stage at Arganil. But Ogier’s blistering run through the Mortágua finale narrowed the gap and intensified the pressure.

“It has been a great battle the whole day,” admitted Rovanperä “I could not do much more [in the last one] because my tyres were in such bad condition at the rear and it was just about surviving.

“[The battle] is only fun if you are winning, so let's see!”

Tyre management played a crucial role during leg one. Pirelli's soft compound rubber was favoured for this morning’s sandy surfaces, while hard tyres came into play in the afternoon when the repeated stages were rougher and temperatures higher.

Ogier’s late surge propelled him from fourth to second overall. He could have potentially led overnight were it not for an intercom failure during SS5 and a loss of hybrid power on SS8.

Katsuta lived up to his promise to push hard from the outset, clinching the Mortágua 1 stage win as well as setting top-three times on both runs of Arganil. He was happy to bring up the rear of a Toyota 1-2-3 overnight despite falling 3.7s behind Ogier, while Ott Tänak completed the day just 0.7s further back in fourth after admitting to a "not nice" feeling behind the wheel of his Hyundai i20 N.

Although Toyota enjoyed a successful day, misfortune befell title-hunting GR Yaris driver Elfyn Evans, whose co-driver Scott Martin resorted to using his mobile phone to access a digital copy of their pacenotes after misplacing the physical book before SS7. Their frustrations were compounded by a tyre being pushed off the wheel rim in the same stage, costing the British pair almost a minute.

That turn of events was a bost for championship leader Thierry Neuville, who headed Evans by six points before this round.

Despite facing the challenge of opening the road and sweeping a cleaner and faster line for those running behind, Neuville managed to stay in touch with the leaders and ended 0.2s behind his Hyundai colleague Dani Sordo in sixth. Sordo lost hybrid power for SS5 but still managed to win three of the day's eight stages.

M-Sport Ford Puma driver Adrien Fourmaux heads Evans on his return to the Matosinhos service park for the overnight halt while Grégoire Munster and WRC2 leader Oliver Solberg completed the top 10.

Saturday marks the longest leg of the rally, with 145 kilometres of action packed into two loops of four stages before the Lousada super special stage concludes the day. SS10, Felgueiras, is up first from 08:05 local time.