Swiatek dominates ahead of New York, while Raducanu eases past Azarenka
World number one Iga Swiatek beat former US Open winner Sloane Stephens 6-4 7-5 to start her campaign at the WTA 1000 tournament, the last big tune-up event before the hardcourt major kicks off in New York.
It was a Tour-leading 50th win of the season for two-time French Open champion Swiatek, who will meet Madison Keys in the third round after the American beat Jelena Ostapenko 6-4 7-5.
"I'm trying to really focus on the future and kind of not coming back to expectations and everything that happened on last tournaments on hard court," said the Pole, who lost in the third round in Toronto last week.
"I'm really proud of my season, but I want to kind of really be fearless again."
After thumping Serena Williams 6-4 6-0 in the first round, Raducanu delivered another dominating display, the 10th seed needing just 62 minutes on centre court to dismiss twice Australian Open winner Azarenka.
"I was playing a great match for sure and to play Vika I had to stay focused throughout," said Raducanu.
"In the second set I could feel the important moments and a couple of turning points that could have made the second set really difficult.
"I am really pleased with how I dug in and serving it out in that last game was really difficult."
Raducanu, who has not won a tournament since capturing last year's title at Flushing Meadows as a 150th-ranked qualifier, appears to be hitting her stride with the season's final Grand Slam coming up from August 29 to September 11.
After committing just one unforced error in her match against Williams, the Briton was again firing on all cylinders as she raced out to 6-0 4-0 lead before Belarusian Azarenka was able to hold serve and avoid an embarrassing double-bagel.
Looking every bit the player who stunned the tennis world a year ago with her magical run at Flushing Meadows, Raducanu had all parts of her game working, laying down five aces and unleashing a barrage of returns and a flurry of winners.
She next takes on American seventh seed Jessica Pegula, who rallied to beat Ukraine's Marta Kostyuk 6-7(5) 6-1 6-2.
Wimbledon champion Elena Rybakina barely broke sweat in a 6-3 6-1 win over Garbine Muguruza while Ons Jabeur, her opponent in the grasscourt major final, was pushed hard by hometown favourite Caty McNally.
World number five Jabeur saved three match points to edge the American, ranked 179th in the world, 6-3 4-6 7-6(7) and set up a third-round match against twice former Wimbledon champion Petra Kvitova.
"Honestly, I'm not playing my best tennis right now," the Tunisian told the WTA Tour. "But it's good to win ugly."
Two-time major winner Simona Halep, who won last week's Canadian Open in Toronto, pulled out due of a right thigh injury before her match against Veronica Kudermetova, who advanced to a third-round meeting with Ajla Tomljanovic.
Australian Tomljanovic lost the first set tiebreaker to Spain's world number four Paul Badosa but bounced back superbly to win 12 of the next 14 games for a 6-7(3) 6-0 6-2 victory to close out play on Wednesday.