The No.4-seeded Halep struggled with the No.15-seeded Lisicki's huge game early on, dropping a long 52-minute first set, 7-5, and coming just a few games from losing in the second set, falling behind, 3-2. But she found her range just in time, cutting out some costly unforced errors and hitting her targets more and more, eventually winning 10 of the next 12 games to cruise to victory, 5-7, 6-3, 6-2.
By the end of the match, both players had the exact same amount of winners - 29 to 29 - but Halep was just too tidy on the unforced errors front, hitting 18 less throughout the match - 26 to 44.
"I had a good week in Stuttgart, and I'm just trying to take that confidence into this week," Ivanovic said. "To be honest, I'm not looking further than tomorrow's match. I just like every new opportunity and challenge. Every point is different, and every match is different, and every day is different.
"I'm just enjoying competing. I love clay and it's always good to be back on this surface."
And Madrid is a particularly special venue for Ivanovic. "I really feel a lot of affection when I'm competing on the court here. I feel the support. Even walking around the city and the parks, people come up to me and they're like, 'Oh, good luck, good luck.' It's very sweet and I appreciate that."
Halep and Ivanovic are tied in their head-to-head series, 1-1, both meetings coming last year.
All four quarterfinals were set in stone on Thursday, arguably the most tantalizing of them all being the one between Li Na and Maria Sharapova, after the No.2-seeded Li beat No.16 seed Sloane Stephens, 2-6, 6-3, 6-2, and the No.8-seeded Sharapova outslugged Sam Stosur, 6-4, 6-3 (read more here).
That's not the only all-Top 10 clash coming up on Quarterfinal Friday - Serena Williams and Petra Kvitova will square off too, after the No.5-seeded Kvitova beat Lucie Safarova, 6-4 6-3, and the No.1-seeded Williams outdid No.14 seed and Spanish No.1 Carla Suárez Navarro, 6-2 6-3 (read more here).
The other quarterfinal will pit Agnieszka Radwanska against Caroline Garcia, after the No.3-seeded Radwanska beat Roberta Vinci, 6-1, 6-1, and Garcia - a French qualifier, and one of the WTA's most promising rising stars - outrallied No.10 seed Sara Errani, 6-2, 4-6, 6-3 (read more here).
All four quarterfinals are on Friday - check WTA TV developed by Xerox to see where you can watch!