Rafael Nadal warned his rivals he was close to again getting the most out of his forehand after coasting into the US Open second round despite his wrist worry.
The Spaniard went into the year's last grand slam still battling a wrist injury, but had no problem disposing of Uzbek Denis Istomin 6-1 6-4 6-2 in his opener at Flushing Meadows on Monday.
Nadal, a 14-time grand slam champion including twice in New York, said he was slowly regaining form on his forehand - in a worrying sign for his rivals.
"My serve worked well almost all the time. I am hitting very well the backhand, but it's true that the forehand I need time," he said.
"I need confidence and I need to keep practicing the forehand. It's not easy to go two and a half months out of competition in the middle of the season without hitting a forehand.
"I need to have the confidence again with my wrist. That is coming, because I feel the wrist much better, and every day feel that the wrist a little bit better. That's very important thing for me. By the way, the most important thing.
"I need to recover the normal movement with the forehand. Even if I played very well in Rio [at the Olympics] when you have pain you try to change the movement to avoid a little bit that pain.
"I need to find again the normal movement. But I am on the way."
Nadal made his return from the injury at Rio 2016, winning a doubles gold medal and reaching the semi-finals in singles before losing the match for bronze.
The 30-year-old, who faces Andreas Seppi in the second round, said his efforts at the Games had a huge impact.
"It was too tiring. After the Olympics I felt myself destroyed. But it's normal," he said.
"It's not because I was not ready. It's because I didn't compete and I didn't have the chance to practice strong practices on court. I was doing a lot of physical performance, training in the gym."