The No.1-seeded Li fought through windy and at times rainy conditions to get past the Australian qualifier in an hour and 17 minutes in the feature night match on center court, 6-1, 6-4.
Li's numbers on the match were very solid - she had a positive differential of winners to unforced errors (23 to 21), compiled an 84% first serve percentage and converted five of seven break points.
Li is the 12th active player to reach 500 career match wins - at all levels - after Venus Williams, Serena Williams, Jelena Jankovic, Flavia Pennetta, Tamarine Tanasugarn, Francesca Schiavone, Nadia Petrova, Maria Sharapova, Daniela Hantuchova, Svetlana Kuznetsova and Stéphanie Foretz Gacon.
The other two second round matches produced upsets, both of which were absolute grinders, starting with Czech qualifier Petra Cetkovska rallying from a set down - as well as a break down in the second set, and twice a break down in the third set - to upset No.7 seed Angelique Kerber, 4-6, 6-3, 6-4.
Petra Kvitova followed Kerber to the sidelines later in the day. Zhang Shuai recovered after letting a 5-3 lead go in the second set to finish the No.5-seeded Czech off in three sets, 7-6(6), 5-7, 6-3.
"This was a really good win for me on clay," Zhang said. "I played a few tournaments on clay this year and lost first round at all of them, so it's good to see the hard work I've been doing has paid off.
"Petra's a top player - every time I played well, she'd play even better, and whenever I thought I was close to winning the match, she'd play better. So I'm really happy I could get this win in the end."
Cetkovska's win over Kerber was the ninth Top 10 win of her career, while Zhang collected the second Top 10 win of her career - her first came against a No.1-ranked Dinara Safina way back in 2009.
The first round wrapped up earlier in the day, and there was a big upset there too, and one that certainly got the home crowd on its feet. Camila Giorgi, an Italian wildcard, pulled off a stunner over No.9 seed Dominika Cibulkova, originally storming out to a 6-4, 5-2 lead and - after missing out on some big chances in that second set, including a match point at 6-5 - closing it out, 6-4, 7-6(2).
The other seeds in first round action both won, with No.10 seed Errani beating South African qualifier Chanelle Scheepers, 7-5, 6-3, and No.13 seed Carla Suárez Navarro beating German qualifier Mona Barthel, 6-2, 6-2. Suárez Navarro's win over Barthel was her WTA-leading 29th match win of the year.
Other first round winners were Ekaterina Makarova, Garbiñe Muguruza and a trio of qualifiers - Monica Puig, Christina McHale and Belinda Bencic. Those three WTA rising stars all scored wins over higher-ranked players - Daniela Hantuchova, Sorana Cirstea and Anastasia Pavlyuchenkova, respectively.