"I think I played my best match of the year," Halep told WTA Insider after the match. "I was confident, and knew what I had to do: push and make her run. I hit some winners, which was very good for me. I was moving well, so I think everything went pretty well for me tonight."
The Romanian has been plagued by knee issues throughout the 2017 season, forced to pull out of the St. Petersburg Ladies Trophy and the Middle East Swing to heal the injury.
Coming into Miami, the former French Open finalist had yet to win back-to-back matches this year, but struck down that stat in decisive fashion on Sunday night, rolling past Kontaveit in 55 minutes.
"I felt good when I came to site, and was sure that it was going to come together because I work every day. At one point, it has to come.
"I felt the best that I have this year. I can move without pain or anything, and I'm confident, which is the most important thing."
Kontaveit is a talented youngster in her own right, a former junior Slam finalist who knocked out No.32 seed Ekaterina Makarova en route to the third round, but had no answers to her opponent's unstoppable form, her 17 winnes undone by 24 errors in total.
"My first match here was close," she said of her opener against Naomi Osaka. "I had some trouble in the first match. After that, I saw that I could resist and stay strong. Today, everything was flowing. I didn't plan anything, and I won't plan anything else. I just want to go there and give my best."
Incredibly aggressive under the lights, Halep struck 19 winners to just 13 unforced errors and broke serve five times to book a round of 16 match-up with 2011 US Open champion Samantha Stosur.
"It's going to be a tough match, for sure. I know how I have to play, because she's very dangerous. Her forehand is strong, and so is her serve. I'm here to do my job, and to try to win because that's what I want.
"Nothing special. I just expect a tough one and I'll go there to fight."
Halep and Stosur last played at Roland Garros 10 months ago, when the Aussie won on a wet and rainy day in Paris, locking up their head-to-head at four wins apiece.
The former World No.2 has won their last four hardcourt matches, though two of those three required a third set. But Halep might have a secret weapon.
"Something is waiting for me already, a Nutella crepe. I've eaten one every day, and maybe that's why I'm winning!"
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This article was first seen on www.wtatennis.com.