Sebastien Loeb continued to lead the Rally of Spain after SS12, but a stellar drive from Ford's Jari-Matti Latvala allowed him to close to within 27.6s of the Frenchman.
The asphalt stages seemed to offer Loeb a chance to further extend his lead, but instead he ended up dropping just over five seconds to Latvala.
The Finn was faster on SS10 and SS12, and surrendered just 0.2s on SS11 to keep the pressure up on the seven-time champion.
"It's been the best day of my career ever on Tarmac," Latvala said following SS12. "I haven't been able to catch [Loeb] much, but still I need to be pleased. I can pressurise tomorrow."
After losing some of his advantage on the asphalt, Loeb said he was surprised at Latvala's pace and admitted he would have to respond to the Finn's charge tomorrow.
"Latvala is going very, very fast," Loeb said. "It's surprising on [asphalt], but I have a good feeling in my car - no problem at all.
"We have to push because Latvala is pushing hard. Tomorrow we have a 30s lead."
As Latvala gained, his Ford team-mate Mikko Hirvonen - currently tied on points with Loeb at the head of the championship - continued to struggle.
Hirvonen dropped time to Latvala on all three stages, including a sizeable 21s loss on SS10. He was able to gain time on Loeb in the final stage however, and also give himself a little breathing space over Mini's Dani Sordo.
The Spaniard made inroads into Hirvonen's advantage in SS10 and was then quickest of all in SS11, but his pace tailed off a little in the final stage to leave him 37.4s behind the Finn.
Leading positions after SS12: Pos Driver Team/Car Time/Gap 1. Sebastien Loeb Citroen 3h06m01.3s 2. Jari-Matti Latvala Ford + 27.6s 3. Mikko Hirvonen Ford + 1m51.8s 4. Dani Sordo Mini + 2m29.2s 4. Sebastien Ogier Citroen + 3m41.4s 6. Kris Meeke Mini + 4m11.9s 7. Mads Ostberg Stobart Ford + 4m49.1s 8. Henning Solberg Stobart Ford + 6m42.0s 9. Evgeny Novikov CRT Citroen + 7m19.8s 10. Matthew Wilson Stobart Ford + 8m48.8s