Sebastien Ogier heads into the final day of Rally Catalunya with a slender lead over Dani Sordo following a charge on Saturday's afternoon loop.
Continuing his blistering pace from Saturday morning, Ogier was quickest on three of the afternoon's four stages and in the space of just 41.98 stage miles had turned a 7.7-second deficit after SS11 into a lead of 5.8s by the end of the day.
Determined to fend off Ogier's challenge and secure his first World Rally Championship victory for Hyundai on home soil, Sordo pushed as hard as he could, but had no answer for Ogier's form.
Battling persistent understeer, the Spaniard was forced to give up the lead on SS14, then surrendered another 4.1s on the 1.39-mile superspecial in Salou.
Ogier only needs to a score single point to clinch a fourth WRC title after his closest championship rival Andreas Mikkelsen crashed out in dramatic fashion on SS12.
Carrying too much speed into a fast right-hander, Mikkelsen's Polo clipped the end of the armco barrier and was tipped into a frightening sequence of barrel rolls, before coming to rest against a tree.
The Norwegian and co-driver Anders Jaeger emerged unscathed, but with their slim title hopes in tatters.
Mikkelsen's demise promoted Sordo's team-mates Thierry Neuville and Hayden Paddon to third and fourth places respectively, with Kris Meeke 37.9s behind in a lonely fifth.
The Northern Irishman survived a fifth-gear spin on SS12 with only light cosmetic damage and ended the day by setting the fastest time on the superspecial.
Meeke has healthy margin of 37.8s over Mads Ostberg in the sole remaining M-Sport Ford, after Eric Camilli was forced into retirement with transmission problems.
Ott Tanak, Kevin Abbring and Martin Prokop occupy the lower reaches of the top 10, while WRC2 leader Jan Kopecky sits 10th overall despite a puncture on SS13. The Czech has a 14.3s lead over Pontus Tidemand.
Craig Breen survived a spin on the superspecial to end the day 13th after driveshaft problems cost him several minutes in the morning, while Jari-Matti Latvala bounced back from a puncture on SS12 to set the second fastest times in SS13 and 14, but is still some way off the points in 17th position following his suspension problems on Friday.
LEADING POSITIONS AFTER SS15-