Sebastien Loeb leads in Sardinia after an eventful opening morning, despite the Citroen driver running first on the road.
Loeb found the slippery surface tough on the first stage and was only eighth, but made great progress thereafter, and moved ahead of Mikko Hirvonen's Ford to take the lead on SS4 Monte Grighini Sud.
Hirvonen admitted that it "looks like Sebastien found another gear" and is now 2.7 seconds behind the world champion heading to the midday remote service.
The big news behind the lead battle was the performance of the new Mini in Kris Meeke's hands. On the car's debut, Meeke got up to fourth place by the end of SS2, before a suspected technical problem resulted in him hitting a rock on the next stage. Dani Sordo holds eighth in the sister car.
Jari-Matti Latvala has already retired the second Ford. He tipped the car on its side in an SS1 accident, consequences of which forced him to park during SS2.
"Unfortunately [co-driver] Miikka [Anttila] did a mistake - he called a wrong note," said Latvala. "But we have done so many rallies together and it was the first time."
Petter Solberg had led at first, before a turbo pipe problem on SS2 cost him 40s. He was already begun regaining the lost ground and is up to sixth in the Solberg Citroen.
Evgeny Novikov holds an excellent third, just ahead of his Stobart team-mate Mads Ostberg. Both had trailed fellow Stobart man P-G Andersson as the one-off returnee held third early on, but Andersson had to stop and change a steering arm after a brush with a rock, which cost him 16 minutes.
Sebastien Ogier is an unusually muted fifth at present.
"It's difficult for me to get a good rhythm," he said. "In some parts I was cautious for sure, but in other parts I tried and could not get a rhythm. It's okay - we are still in the race, that's most important."
Leading positions after SS4:
Pos Driver Team/Car Time/Gap
1. Sebastien Loeb Citroen 44m35.2s
2. Mikko Hirvonen Ford + 2.7s
3. Evgeny Novikov Stobart Ford + 11.9s
4. Mads Ostberg Stobart Ford + 19.8s
5. Sebastien Ogier Citroen + 20.8s
6. Petter Solberg Solberg Citroen + 26.3s
7. Henning Solberg Stobart Ford + 42.4s
8. Dani Sordo Mini + 45.5s
9. Ott Tanak MM Ford + 1m02.2s
10. Martin Prokop Czech Ford + 1m11.2s