Hyundai's Dani Sordo leads after the first three stages of Rally Mexico's Friday leg, with returning nine-time WRC champion Sebastien Loeb sat in third.
Sordo, who missed Rally Sweden as he shares his Hyundai with Hayden Paddon this year, was second behind Kris Meeke in SS2, the opening stage of the day, and then dominated the subsequent 31.44km El Chocolate run.
The Spaniard already had a lead of nearly 10 seconds at that point, but he further extended his advantage to 15.1s by also topping SS4.
Meeke is best of the rest in second overall but he is only 3.1s ahead of Citroen teammate Loeb, who is tackling his first WRC rally since the 2015 Rally Monte Carlo.
Loeb was in the top four in all three stages and only missed out on winning SS4 by 1.9s.
Ott Tanak leads Toyota's efforts in fourth as both of his teammates Jari-Matti Latvala and Esapekka Lappi, sitting eighth and 10th respectively, struggled with engine overheating.
Sebastien Ogier is over half a minute adrift in fifth. The Frenchman is second in the running order behind championship leader Thierry Neuville, but Ogier reckons that's still a significant disadvantage.
"Its going to be a killer for us, I cannot see a line from him [Neuville] to be honest, it's still quite loose. The guys behind are going to be quicker," said Ogier after SS2.
Andreas Mikkelsen is narrowly behind Ogier in sixth, with Neuville in seventh place.
Teemu Suninen is between Latvala and Lappi in ninth, while fellow M-Sport driver Elfyn Evans is last of the 11 main-class competitors as the Welshman temporarily stopped on SS4 and lost over two minutes.
Rally Mexico's Friday morning leg will conclude with a 1.11km Street Stage in Leon.
UPDATE: Suninen beat Mikkelsen by a tenth of a second to top the Street Stage. Neuville meanwhile suffered an engine failure and lost 26 seconds, forcing him to drop behind Latvala and Suninen to ninth.