CHARLESTON, SC, USA - Winning her second match in less than 24 hours, No.7 seed Madison Keys moved into the quarterfinals at the Volvo Car Open for the third time in her career with a 6-4, 6-3 win over the always-dangerous Camila Giorgi.

The big-serving American saw a 5-1 lead in the first set nearly slip away but broke to pocket a one-set edge, was much more effective behind her delivery in the second set.

In it, Keys saved all four break she faced, and served six of her eight aces for the match - including two in the final game, with one on match point.

"She'll hit three amazing winners, and then she'll miss two, so she's always really tough to play. I was just trying to put one more ball in the court," Keys told Tennis Channel after the match.

"To get back-to-back matches [won] feels really good. I just always have really great memories of being here, and I always feel like I'm playing well."

Keys, who lost the last match she played against the Italian at Wimbledon a season ago, did not have the slow start which was a hallmark of that encounter. 

Two emphatic holds of serve helped the American set the tone for the match, and she nabbed the first break in the fourth game to move ahead further.

After saving a break point, Keys added the insurance she sought in the sixth game, building a 0-30 lead and breaking on her second opportunity.

However, the Italian found her power game over the ensuing games, getting a read on return and winning three straight games to get the set back on serve, never allowing the No.7 seed a set point opportunity. 

"I went up 5-1 playing one way and then playing the exact same way, it was 5-4 all of a
sudden," Keys reflected after the match. 

"It's really just weathering the storm and looking for opportunities when you can, and I'm really happy that I stayed calm and patient when things could have easily spiraled the other way."

However, after a changeover chat with coach Lindsay Davenport, Keys went back to work and broke Giorgi for a third time - the first to love in the match - to seal the set, capping it emphatically with a sweetly-struck forehand pass.

"It's hard to be on the offense on [her ball], but it's also you kind of  you don't know if she's going to hit a winner or a mistake, so you kind of want to test her sometimes," Keys said of the mercurial Italian.

"I also think that for me sometimes I overadjust. If I feel like I'm missing the shot, all of a sudden I start pushing, which makes me miss it even more. Sometimes, I do need the reminder to swing and actually commit to the ball."

Keys stayed steady in the middle of the second set, as a break in the fourth game on her third opportunity put her in command of the match, before she survived four break points on her own serve to build a 4-1 lead. 

Acknoledging the pressure that Giorgi's hyper-aggressive tennis put on her over the course of one hour, 18 minutes, Keys also gave credit to the changeover discussions with Davenport which helped her push through to victory.

"The biggest thing was make sure you;re going for your shots. I feel like I got a little bit passive in the first set, and in the second set, [Davenport] mostly was just talking about
service games, like saying, 'Go for your serve, pick a spot, really go for it,'" Keys said. 

"In the second set, I think I won like eight of  nine points after that. It was really good just to kind of settle my nerves and have something to focus on."

Keys will next face compatriot Bernarda Pera, whose breakout fortnight continued with a 6-3, 2-6, 6-4 win over wildcard and former French Open finalist Sara Errani.

Against Keys, the 23-year-old American will be contesting her first tour-level quarterfinal.

"I don't know a ton. I never really hit with her. I've seen her a little bit this year because
she's been winning some matches," Keys assessed. "But other than she goes for her shots and she's a lefty, I don't know much.

"I feel like I have pretty good momentum. I think I served really well today. There was a lot of things that I did well, so I think if I just focus on what I was doing well and what I need to do, then I'm not really concerned about who's on the other side."