MELBOURNE, Australia -- World No.1 Iga Swiatek began her 2023 Australian Open campaign with a hard-fought 6-4, 7-5 win over Germany's Jule Niemeier. Swiatek will face Colombia's Camila Osorio in the second round on Wednesday.

More from Day 1:

A semifinalist in Melbourne last year, Swiatek worked hard in her opener. The 21-year-old made clear before the tournament she was not taking Niemeier lightly, and the German once again proved to be a tough matchup for the World No.1.

Facing each other for the second consecutive Slam, Niemeier had already Swiatek to three sets in their last meeting in the Round of 16 at the US Open. 

How the match was won: Niemeier maintained sustained pressure on Swiatek's serve throughout the opening set, but when the Pole needed a clutch serve or big backhand down the line, the shots came through. Swiatek withstood the pressure and saved the two break points she faced and then pounced at her first chance to break, breaking the German's serve for the first time to win the opening set.

"Honestly, I really wanted to be focused on myself because I know Jule can serve amazing," Swiatek said. "At the US Open she was really using the fast conditions that we played in."

Niemeier struck back quickly in the second set, earning a first break of the Swiatek serve to build a 3-1 lead and had a slight opening to earn a double-break lead. But Swiatek once again came up clutch to dig out of a deuce game to close the gap to 3-2. Serving to take the match to a decider, Niemeier was broken in Swiatek's best return game of the match to level the score at 5-5.

From there, the Swiatek comeback was on. She held at love to move ahead to 6-5 and then played an outstanding return game to seal her four-game and secure the win after 1 hour and 59 minutes. 

Swiatek on managing expectations: "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 told reporters 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."

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Stat of the match: Swiatek is on a 19-match win streak at the Grand Slams when she wins the first set. 

Rybakina rolls past Cocciaretto

Wimbledon champion Elena Rybakina passed a stern test to preserve her unbeaten record in the Australian Open first round, defeating Elisabetta Cocciaretto 7-5, 6-3 in 1 hour and 23 minutes.

Cocciaretto, 21, was coming off her maiden Hologic WTA Tour final in Hobart last week, a result that has enabled the Italian to make her Top 50 debut this week at No.48. After a slow start, she kept No.22 seed Rybakina on her toes throughout.

Highlights: Rybakina d. Cocciaretto

The 23-year-old Kazakh required six set points to close out the first set after Cocciaretto pegged her back from 5-2 to 5-5 with a flurry of forehand winners. In the second, Rybakina had to overturn an early break deficit before pulling away.

But a stolid approach to the scoreboard fluctuations paid off. Rybakina swatted a clean return winner to convert her sixth set point in the first set, as though unbothered by having been unable to close out the previous five. Another return winner would bring up her first match point. In total, she would fire 24 clean winners, including five aces.

Rybakina will face Kaja Juvan in the second round.