Iga Swiatek kicked off her WTA Finals title defence with a hard-fought victory, rallying back from a set and a double-break down to overcome eighth-seeded Barbora Krejcikova in Riyadh on Sunday.
World number one and defending champion Iga Swiatek withdrew from the prestigious Beijing 1000 WTA tournament on Friday citing "personal matters".
Jessica Pegula became the fourth American to reach this year's US Open semi-finals by stunning world number one Iga Swiatek as Jack Draper broke through to his first Grand Slam last-four.
Iga Swiatek said a chat with Serena Williams as the 23-time Grand Slam champion toured the US Open grounds on Saturday was a "positive kick" before her third-round victory over Anastasia Pavlyuchenkova
Jannik Sinner avoided plunging through the US Open trapdoor which claimed Novak Djokovic and Carlos Alcaraz when he stormed into the last 16.
Swiatek needed only 1 hour and 5 minutes in a 6-0, 6-1 rout.
Jannik Sinner is the top seed among men, fresh from a clean chit after doping allegations.
Aryna Sabalenka squandered nine match points but defeated world number one Iga Swiatek 6-3, 6-3 on Sunday
World number ones Jannik Sinner and Iga Swiatek both turned around losing situations on Saturday to move into the semi-finals of the ATP and WTA Cincinnati Open.
Zheng Qinwen ended Iga Swiatek's 25-match unbeaten streak at Roland Garros on Thursday to become the first Chinese player to reach an Olympic Games singles final