Having won all three previous encounters, the No.4-seeded Li hit more than three times the winners as Cibulkova - 33 to 9 - and followed up a tight first set by rolling through the second set, 76(1) 62.
"It was very tough to win the first set, but once I got it, I was thinking, 'Okay, one set in the pocket, so just keep hitting the ball,'" Li said after the match. "In the second set I was just continuing what I was doing and not looking at what she was doing anymore. I was feeling very good in the second set."
There was one thing Li thought she could have done better though, after a little stats analysis. "I was thinking today I didn't have a lot of winners, but I was checking the information after the match and I still had 33," the Chinese said. "I thought that I could have still hit more winners in the match."
And about her perfect record against Cibulkova, who has a whopping 19 Top 10 wins to her name?
"I've never lost to her, but every time is tough," Li said. "She's running pretty fast on the court and she can hit everywhere on the court, so we never have an easy one. I really have to be ready for every second out there, otherwise I'll lose the point. So she's still a very tough opponent for me, for sure."
Next up for Li will be Cirstea, who took out her third straight seed - having taken out No.9 seed Caroline Wozniacki and No.15 seed Jelena Jankovic the last two rounds, the Romanian battled past No.6 seed Petra Kvitova, winning seven straight games from 64 54 down and eventually winning, 46 75 62.
"I tried to go on the court with a positive mentality and tried to take the lead early on, but it didn't really happen," Cirstea said. "There were a few moments that were up and down but I'm happy with the way I played. I fought hard for the win and managed quite well in the most important moments today.
"But I don't think for me and my team these results are such a surprise - we have been working very hard on everything and from week to week I've been getting better, so it's kind of a natural step."
"I was defending champion, but still it's a new tournament, and I wasn't thinking like this," Kvitova said. "I'm glad I was in the quarterfinals. I played three matches here, and it's important to play some matches before the US Open as preparation. Of course I'm sad because I have pretty nice memories from last year and couldn't do it this year, but I'm still feeling positive about everything here.
"The important thing now is just to think about the next day and the next tournament."
Li leads Cirstea in their head-to-head series, 4-1, Cirstea's win coming on grass at Wimbledon last year (Li's four wins are split between the other two surfaces - two on hardcourts and two on clay).
"I've actually played Li Na quite a few times now. We know each other. I think last year we played three or four times," Cirstea said. "It's going to be a very, very good match. She's always a very solid player. She's quite aggressive. I just have to do the same things as I've done until now and we'll see."