The seventh-seeded Li, who bested then-reigning champion Francesca Schiavone in last year's finale, handled Sorana Cirstea of Romania 6-2, 6-1 to advance.
Li's 2011 victory was the first ever in a Grand Slam event for an Asian male or female. She now goes on to face France's Stephanie Foretz Gacon.
Also logging a first-round victory was world No. 1 Victoria Azarenka, who had to stage a rally and overcome 60 unforced errors to get past Italy's Alberta Brianti, 6-7 (6-8), 6-4, 6-2.
The Belarusian now will play Germany's Dinah Pfizenmaier in the second round.
Third-ranked Agnieszka Radwanska of Poland advanced as well with a 6-1, 6-0 pasting of Serb Bojana Jovanovski. Her next opponent will be unseeded seven-time major titlist Venus Williams.
No. 8 seed Marion Bartoli of France, Kazakhstan's Sesil Karatantcheva, American Bethanie Mattek-Sands, 15th-seeded Slovak Dominika Cibulkova, Sweden's Sofia Arvidsson, 18th-seeded Italian Flavia Pennetta and 19th-seeded Jelena Jankovic of Serbia also registered Day 2 wins.