World No. 1 Iga Swiatek of Poland was pushed in her first-round match of the Australian Open but escaped with a 6-4, 7-5 win over Germany's Jule Niemeier on Monday in Melbourne.

Swiatek, a three-time Grand Slam champion, fought off two break point chances for Niemeier in the seventh game of thefirst set, then broke her opponent's serve in the final game of the set for the win.

Niemeier grabbed a break of her own early in the second set to go up 3-1, but Swiatek battled back, breaking Niemeier in her final two service games to advance in just under two hours.

With 2022 champion Ashleigh Barty in retirement, Swiatek came in as the favorite and said she carried that burden into the first round.

"For sure I feel the expectations, that people kind of little bit -- they want to take for granted that I'm going to win those first rounds," Swiatek, 21, said after the match. "It's always not easy. Every match is a different story. You have to really work hard to make it done, to win.

"It just feels like sometimes, they're not treating you still as a human, but more like a robot who has to win."

Monday was mostly a good day for the seeded American contingent of women, with No. 3 seed Jessica Pegula, No. 7 Coco Gauff, No. 10 Madison Keys and No. 13 Danielle Collins all moving into the second round. Marta Kostyuk of Ukraine defeated No. 28 Amanda Anisimova in straight sets.

In the matchup of the only two former Australian Open champions in the field, No. 24 seed Victoria Azarenka of Belarus topped Sofia Kenin of the United States 6-4, 7-6 (3).

Gauff, who is playing in her fourth Australian Open at age 18, said she was happy with her performance in her opening 6-1, 6-4 win against Czech Republic's Katerina Siniakova.

"Really pleased with myself," Gauff said. "Katerina is a fighter I knew she was going to fight until the last point and she proved that today. I'm glad I stayed mentally right there."

Next up for Gauff is 2021 U.S. Open champion Emma Raducanu of Great Britain, a 6-3, 6-2 winner over Germany's Tamara Korpatsch.

Among other former Grand Slam champs, 2019 U.S. Open winner Bianca Andreescu of Canada ousted No. 25 seed Marie Bouzkova of the Czech Republic in straight sets; two-time Wimbledon champ and No. 15 seed Petra Kvitova also won in straight sets, as did her fellow Czech, No. 20 seed Barbora Krejcikova, who triumphed in 2021 at Roland Garros; and 2022 Wimbledon champ Elena Rybakina of Ukraine, the No. 22 seed.

Other seeded players to advance were No. 6 Maria Sakkari of Greece and No. 17 Jelena Ostapenko of Latvia.

--Field Level Media