Errani had lost to Varvara Lepchenko in Fed Cup earlier this year, which represented Lepchenko's first Top 10 win - the No.7-seeded Italian wasn't about to give the American her second, grinding out of 3-0 and 4-2 deficits to win the first set then eventually running away with it, reeling off the last 11 points of the match to close out the second set and make the quarterfinals after a tight two-setter, 75 63.
"The court was very wet at the start and I started really bad - and she started very well," Errani said. "It wasn't easy to run for me at the beginning but then I started to feel much better as the match went on.
"I'm very happy to be in the quarterfinals of such a big tournament like this."
Errani and Makarova are tied in their head-to-head series, 1-1, with Makarova winning on clay at an ITF Circuit event back in 2007 but Errani winning their only WTA-level meeting on hard in 2010.
Also moving through to the last eight was Kaia Kanepi, who regrouped mid-way through the second set to close out Daniela Hantuchova in straights, 63 64. Kanepi looked headed for a straight set win as she built a 63 20 lead on Hantuchova, but the former World No.5 won three games in a row to move ahead 3-2 in the second set; Kanepi bounced back though, winning four of the next five games to end it.
"I feel very good about my matches here in Madrid this year, especially because last year I didn't win a match here," Kanepi said afterwards. "I'm really happy to be in the quarters of this big tournament."
Kanepi was asked about her thoughts on the tournament. "It's very well organized," she said, "and it's a different kind of tournament than the others - the club is quite different. I really enjoy it here."
And on Spain in general? "I really like the weather here. I also really like the food. And it's great that everybody is out late - they eat late too. I like it all. I normally don't like travelling anywhere when I'm on holidays, because we're travelling so much all year and I just try to stay home, but maybe one day I will come and see more of Spain on a holiday when I have some time, or why not live in Spain?"
Next up for Kanepi is the No.2 seed, Maria Sharapova, who won through earlier in the day (read more here). Sharapova beat Kanepi in the pair's only previous meeting, at last year's French Open.
"I played her last year at the same time almost, in the French quarters," Kanepi said. "I'm really looking forward to the match. She's the favorite in the match, of course. I just hope to get a good match."
Kanepi's gameplan is simple: "I have to be aggressive and just hit my shots in the court!"