Playing back-to-back on Court 1, the No.2-seeded Li was the first of the pair to advance, winning the first seven games and eventually beating No.15 seed Carla Suárez Navarro in just 61 minutes, 60 62.
"I feel pretty good," Li said. "I was waiting for the Radwanska match before me. At the end of the second set I was already warming up, but then they went to a third set - so I was like, 'Okay, wait.'
"But when we finally got on court I was playing pretty well."
Li had a secret weapon going into the match with the Spanish No.1: "My husband hits a pretty similar ball to Navarro," she said, "a little bit of topspin, a one-handed backhand. It was good for me."
The No.10-seeded Wozniacki followed with an even more dominant 60 61 win over Varvara Lepchenko, though it had the same match time of 61 minutes. Wozniacki had beaten No.17 seed Sloane Stephens the night before, 61 60, so has won 24 of the last 26 games she has played.
Li leads Wozniacki in their head-to-head series, 3-2. Wozniacki won their last meeting, though.
Li was asked about her famous semifinal match with Wozniacki at the Australian Open back in 2011.
"Yeah, I was match point down, right? I saved match point?" she recalled. "For sure it was not an easy match. But it's already been a couple of years since I've played her, so I need some information.
"My coach was going to watch a few games of her match to get that information for me."
Wozniacki will be going for the equal-biggest win of her career in terms of ranking when she takes on the No.2-ranked Li on Wednesday. She has one win over a World No.2, beating Vera Zvonareva in the semifinals of the WTA Championships in 2010 (she would eventually finish runner-up to Kim Clijsters).
A former No.1, Wozniacki is 1-9 overall against Top 2 players (0-2 against No.1s, 1-7 against No.2s).