Two-time champion Naomi Osaka overcame a flurry of mistakes to fight past Czech Katerina Siniakova 6-2 5-7 6-1, finding her mettle to reach the third round of the US Open on Thursday.
The 13th seed has spent years taming her own tendency toward self-recrimination, and showed the best evidence of her new career outlook as she reclaimed her composure with a bathroom break before the third set at Arthur Ashe Stadium.
"The match was definitely really tough. I don't know, I just felt like I had to fight," said Osaka, who will next play Belgian Elise Mertens, who registered a 6-2 7-6 (5) win over Uzbekistan's Maria Timofeeva.
Elsewhere, Iga Swiatek displayed complete control as the 2022 champion dispatched Argentinian Nadia Podoroska 6-3 6-2 to advance to the third round.
The Polish eighth seed sealed the victory in one hour and 10 minutes.

Luiten leads the way at DP World Tour Championship
Jake Paul hails Dubai as "perfect place" for Christmas Eve comeback fight
Derron and Taylor-Brown renew T100 title fight in Dubai
Manchester United sack Carrick, talks ongoing for Pochettino
Ferdinand admits doubts over Pochettino's impact on Manchester United
