Serena Williams insists her shoulder problem is not harming her performance after the American dispatched Ekaterina Makarova in the US Open first round.
Williams wore compression sleeves on both arms in Arthur Ashe Stadium but showed no visible sign of weakness as the world number one cruised to a 6-3 6-3 victory against the Russian.
She shot 12 aces with her faulty right shoulder and Makarova failed to create a single break point as Williams booked a second-round meeting with fellow American Vania King.
“No, I didn’t make too many adjustments,” Williams said.
“I didn’t hit my serves as hard as I normally hit them. I just went for more placement. I didn’t go for the big 120s, just the regular.”
Williams is bidding to win a 23rd grand slam title at Flushing Meadows, which would take her above Steffi Graf’s Open-era record and within one of Margaret Court’s all-time best.
She added a note of caution to any optimism about her fitness, however, admitting she increasingly feels pain the day after a match.
“Usually it’s the day of (playing that I feel it),” Williams said.
“But as time has progressed, and this past week it’s usually been the day after, so that’s a really positive thing.”
Elsewhere, Eugenie Bouchard crashed out in the first round but said she has not been distracted by her ongoing lawsuit against the tournament.
Bouchard is suing the grand slam and the United States Tennis Association after slipping on a wet changing room floor last year and having to withdraw from the competition.
The Canadian’s misery at Flushing Meadows continued as she was beaten 6-3 3-6 6-2 by world number 72 Czech Katerina Siniakova.
“I am 100 per cent focused on tennis and I have lawyers who are working on the case and I don’t think about it often at all, maybe once a month when they call me,” Bouchard said.
“I’m disappointed with what I think happened so I have to fight for what I think is right.”
Venus Williams joined her sister in the second round after edging past Ukraine’s Kateryna Kozlova 6-2 5-7 6-4.
Venus, now 36, has never lost a first round match in 18 appearances here but the veteran was pushed all the way by her world number 93 opponent.
“I didn’t know much about her game at all, literally zero, and it’s hard,” Williams said.
“I haven’t played a single match in three weeks. Just getting out there and trying to play perfectly.
“I definitely had a lot more errors than I wanted. If I could cut those in half, it’s definitely a different story.”
Poland’s Agnieszka Radwanska and Romanian Simona Halep, the fourth and fifth seeds respectively, are also safely through.