It was only a matter of weeks ago when Li routed Jankovic in the fourth round of the US Open - she won in 57 minutes, 63 60 - but this time it was a much different story, as the two battled two hours and 11 minutes before the No.4-seeded Li emerged with a 63 26 63 win over the No.7-seeded Jankovic.
It was an extremely streaky match - never did either player win fewer than two games in a row at any point - but the critical streak went to Li, who won three straight games from 3-all in the third set.
"Today wasn't only about technique," Li said afterwards. "I think both of us were playing unbelievable today, so it was more mental, and I was really happy I could play well again at the end of the match."
Jankovic had a better winners-to-unforced errors differential in the match (she was -19, Li -24), but Li created more break point opportunities and converted just one more time (she was 6/21, Jankovic 5/9). Additionally, Li was more willing to move forward, winning 19 of the 23 points she played at the net.
This is Li's third time playing this event, but the first time she has won two matches - she went 1-2 in the round robin stage in 2011 and 2012, not qualifying for the semifinals in either of those years.
But she hasn't qualified for the semifinals yet - that will come down to Friday's White Group matches.
"At least I'm one more step now - that's pretty good news," Li said. "I play Vika now. She's always a tough opponent. But right now I have nothing to lose, so I'm just going to play and enjoy the time."
Errani does not have a shot at qualifying for the semifinals anymore - Li, Jankovic and Azarenka are all still in the running for the two semifinal spots up for grabs in the White Group this week.