It has been a career-defining year for Simona Halep. The 27-year-old has enjoyed her top-ranked perch since winning her first Grand Slam at the French Open in June, but all that is under threat. Battling a bad back and a four-game losing streak, Halep of Romania is racing to heal in time for the WTA Finals in Singapore, Oct. 21-28, to defend her No. 1 ranking. This conversation has been edited and condensed.
This has been a big year for you.
It’s been the best year in my career, winning a Grand Slam. Being No. 1 is great, but it is even better to win a Grand Slam. The Australian Open was also a great experience for me. I pushed my limits and saw that everything was possible. I saw that I’m strong and can push myself very hard. I think that tournament helped me believe that I can win one of the biggest tournaments. At the beginning of the year, after Melbourne, I just felt I was really able to win a Grand Slam.
Consistent play has been one of your defining characteristics this year. How have you managed to maintain that level of play?
I’ve enjoyed it more this year. I haven’t been putting negative pressure on myself. If you do that, you can’t handle anything. I’ve been through that before coming in the top. But with experience and tough moments, I learned that if you enjoy it more, and take every tough moment and tournament that you have to defend as a challenge, it’s much better.
Has mental fitness been a key to this year’s success?
Over the last year, I have worked with a psychologist. I work hard on the thinking part. At this moment and at this level, everyone is playing very well. So, I try to get mentally stronger. My psychologist told me I have to control my emotions and be more positive.
She’s taught me to stop the negative thoughts during the matches with some exercises. That’s helped me make an improvement. My problem is that I’m negative — I come from Romania. Romanians are a little bit negative in thinking. Everyone knows that. That’s normal here.
That positive thinking must be important now more than ever since announcing that a recent M.R.I. scan revealed a herniated disk, threatening your ability to finish the year with your No. 1 ranking.
I’m really positive in this moment, even with the injury. I feel the pain, but I’m confident that with exercises, recovery and physical therapy, that it’s going to be O.K. I will not stop playing tennis.
How frustrating is it to feel the limitations of your body when playing with an injury?
It’s tough to play with an injury. It was really difficult to play in China because I didn’t know what I had. I was stressed and worried. But now that I know what is dangerous and what is O.K. to do, it’s easier for me to step on the court and to play my best. Every injury is tough, because mentally and physically you try to protect one part of your body and you use the others more. So, you can get more injuries.
Now that you know it’s a herniated disk, are you less stressed?
I just saw another doctor today, and he told me that I am free to play. The problem is there, the disk has moved. But it’s not that dangerous. It’s not moving day by day. It’s fine. Exercises to make the muscles stronger in that area can push the disk back or just keep it where it is. It’s not that bad. There’s no risk in further damage. I have to do my rehab where I’ll work on my core exercises and get massage therapy. No tennis. I’ll wait until the tournament for that.
How motivated are you to play in the WTA Finals and finish the year at No. 1?
I’m 100 percent motivated. It’s my biggest goal. I’m going to give everything I have in this period to finish No. 1. I can do better than last year. It’s going to be great.