MIAMI -- This past January, Zheng Qinwen struggled to win back-to-back main-draw matches in Australia.

It was at that time she went back to the drawing board. One of the factors she now concedes that led her to a slow start was an ill-advised equipment change. 

"I think I made one wrong choice with my racquet," Zheng told reporters after her three-set win over Liudmila Samsonova in the third round of the Miami Open. "I tried to change some details to add more power. But at the end, I found out it wasn't working for me because in Australia, the entire tournament I felt it was so difficult for me to control the ball. 

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"I think people could see that I had no control. I really tried because I thought it was my problem at the beginning. But when I came back to the old one, I felt much better."

Now after a shaky start, the 2022 WTA Newcomer of the Year is looking dangerous once again.

Reunited with her custom Wilson Pro Staff, Zheng, now ranked a career-high No.23, went on to make her first semifinal of the season, in Abu Dhabi, before an abdominal injury forced her out of back-to-back WTA 1000 events in Dubai and Indian Wells. 

Back in action in Miami, Zheng made her first Round of 16 at a WTA 1000 since Toronto last year. She has done it the hard way, coming back from a set down in both her matches to defeat Irina Camelia Begu and 12th seed Samsonova. 

"I'm just really happy about my performance and my mentality to hold on to the tiebreak and win it," Zheng said. "The second set I went down 0-3. It was pretty crazy, I won six games in a row. 

"Honestly I don't know how I did that. I just focused point by point. I tried to have the mentality of all the best players, and what they do in difficult situations.

"It doesn't matter in what situation. You never give up you always fight for every point. Even when you are up, always be focused, never relax. Doesn't matter if you lose 0-6, 0-5 down, you have to fight for every point. That is the respect for tennis, for this professional sport."

Zheng faces 27th seed Anastasia Potapova in the Round of 16. A champion in Linz last month, Potapova comes into the match after a three-set win against Coco Gauff.

"I played against her a couple of times," Zheng said. "I think she's a good fighter. It will be a tough match as always because I think if you arrive to round four you are tough to beat. You have to be focused on everything to win the match. Let's try and see where I can go."