The Spaniard had led since Friday and faces four stages, totalling 41.90km and ending with the Sassari-Argentiera power stage, on Sunday.
"We end today in the same way we finished on Friday, feeling very positive and pleased with our performance," said Sordo, who won one of Saturday's six gravel stages.
"We have had to be careful to manage our tyres today, making the right selection for each loop and pushing when we could, while also conserving when needed."
The battle for second place was on a knife-edge, with Ogier winning four stages to finish the day 1.5 seconds ahead of Hyundai's Belgian Thierry Neuville.
Championship leader Elfyn Evans was in fourth place for Toyota, 58.4 seconds off the lead. (Reporting by Alan Baldwin in London, editing by Pritha Sarkar)