Ogier never relinquished the lead after moving his Citroën C-3 into front of their four-day encounter on Friday afternoon. He headed Tänak by 30.2sec after the Estonian out-gunned Elfyn Evans at a final-day fight for second.
His 46th career success has been achieved with a third different manufacturer after previous victories with Volkswagen and Ford.
Scorching heat and tough gravel tracks in mountains near León ensured a rally in attrition, but Ogier delivered a measured display due to his second successive Mexico triumph.
He conquered a differential problem and a trip into a tyre wall on Saturday night, also had to maintain a strong pace now to hold the door firmly closed to a charging Tänak.
Ogier, who made his WRC debut in Mexico in 2008, said: “It has ever been a special place as the beginning of my livelihood and I’m thankful it remains that way.
It wasn’t even a troublefree rally for us, however, we managed to make the very best of it came out with maximum points,” included the Frenchman, who also scooped maximum bonus points by winning the Wolf Power Stage by 0.025sec.
Second for Tänak surpassed his dreams. As championship pioneer, the Toyota Yaris driver started the roads in Friday’s first leg and faced the worst of these conditions, devoting large chunks of time ploughing a blank line through thick gravel.
He started the final legin which temperatures topped 30°C, 2.2sec adrift of Evans. He overhauled the Welshman in the opening evaluation to finally end 19.2sec ahead. The group were the only top line drivers to prevent issues in the gruelling problems.
Thierry Neuville and also his Hyundai i-20 were both off-colour on the way to fourth. The Belgian fought disease through the rally and fought for pace in the high-altitude stages. He fell to third at the championship standings behind Tänak.
Kris Meeke finished fifth, his best result since joining Toyota Gazoo Racing. With a enormous time advantage over sixth-placed Benito Guerra, the Ulsterman drove slowly through today’s initial stages to ensure his tyres were at the best condition to chase a Wolf Power Stage triumph, only to be refused by Ogier.
He ended almost 9min 30sec away from dwelling hero Guerra, who obtained WRC 2 in a Skoda Fabia. Marco Bulacia finished seventh and second in the support category, holding off Jari-Matti Latvala, who limped his Yaris through the final stage with a broken radiator.
Dani Sordo and Ricardo Trivino finished the leaderboard.
The championship returns to Europe after this month to get its opening all-asphalt fixture.