"Definitely one of my hardest victories ever -- we had to fight and we had a lot of problems," Tanak, who is now two points off the championship lead, said at the finish on Sunday.
Belgian Thierry Neuville finished second in a Hyundai after Tanak's team mate Kris Meeke retired on the final stage.
Neuville, who won in Portugal last year, was pleased with his performance over the weekend as he rebounded from a terrible crash that ended his previous race.
"After the big crash we had in Chile, it was important to come back fighting," the 30-year-old said.
"Overall, I think we can be pleased with second place. The time we lost on Friday's opening stages is more or less the time we were missing at the end.
"We were lacking a bit of precision today to give it more of a push, but on the whole it’s a good result.
Citroen's Ogier took third spot and remains the championship leader with 142 points, having won the final power stage for five valuable bonus points.
(Reporting by Hardik Vyas in Bengaluru, editing by Pritha Sarkar)
