AP

Women to watch at the Australian Open, where play begins Monday:

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SIMONA HALEP

Ranked: 1

Country: Romania

Age: 27

2018 Match Record: 46-11

2018 Singles Titles: 3

Career Singles Titles: 18

Grand Slam Singles Titles: 1 — French Open (2018)

Last 5 Australian Opens: 2018-Runner-Up, 2017-Lost in 1st Rd, 2016-1st Rd, 2015-QF, 2014-QF

Aces: Will remain at No. 1 at the end of the Australian Open, regardless of results there, giving her 48 weeks in a row at the top spot.

Topspin: Lost last four matches of 2018 before shutting down in October with a bad back. ... Will be interesting to see whether anything is lingering from that — or from her offseason split with coach Darren Cahill, who decided to take a break. Halep is still without a coach.

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ANGELIQUE KERBER

Ranked: 2

Country: Germany

Age: 30 (31 on Jan. 18)

2018 Match Record: 46-19

2018 Singles Titles: 2

Career Singles Titles: 12

Grand Slam Singles Titles: 3 — Australian Open (2016), Wimbledon (2018), U.S. Open (2016)

Last 5 Australian Opens: 2018-SF, 2017-4th, 2016-Won Championship, 2015-1st, 2014-4th

Aces: Ranked among the top seven players in percentage of break-points converted, return points won and return games won in 2018.

Topspin: After a rough 2017, returned to prominence last year with semifinal run in Melbourne, followed by Wimbledon title, and another lengthy stay in Australia would surprise no one for the increasingly aggressive baseliner.

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CAROLINE WOZNIACKI

Ranked: 3

Country: Denmark

Age: 28

2018 Match Record: 41-17

2018 Singles Titles: 3

Career Singles Titles: 30

Grand Slam Singles Titles: 1 — Australian Open (2018)

Last 5 Australian Opens: 2018-W, 2017-3rd, 2016-1st, 2015-2nd, 2014-3rd

Aces: Only woman to rank among the top 10 on tour last year in both percentage of service points won and return points won.

Topspin: After life-altering developments in 2018 — first career Grand Slam trophy in Australia, then diagnosis of rheumatoid arthritis — how will she begin 2019?

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NAOMI OSAKA

Ranked: 4

Country: Japan

Age: 21

2018 Match Record: 40-20

2018 Singles Titles: 2

Career Singles Titles: 2

Grand Slam Singles Titles: 1 — U.S. Open (2018)

Last 5 Australian Opens: 2018-4th, 2017-2nd, 2016-3rd, 2015-Did Not Play, 2014-DNP

Aces: Breakout season included first two WTA titles and run to U.S. Open trophy in September showed the world what those in tennis have seen for quite some time: She has booming shots and an in-match confidence to match.

Topspin: Some players have trouble adjusting to the added pressure and expectations of being a major champion for the first time; Osaka — aided by coach Sascha Bajin, who used to work with Serena Williams — doesn't seem to be that sort of athlete.

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SLOANE STEPHENS

Ranked: 5

Country: United States

Age: 25

2018 Match Record: 37-19

2018 Singles Titles: 1

Career Singles Titles: 6

Grand Slam Singles Titles: 1 — U.S. Open (2017)

Last 5 Australian Opens: 2018-1st, 2017-DNP, 2016-1st, 2015-1st, 2014-4th

Aces: Tied for WTA lead in 2018 with five victories over opponents ranked in top 5. ... First-serve percentage of 69.6 led tour last year.

Topspin: Hasn't won a match in Melbourne since 2014, but was a semifinalist in 2013 and is a far more complete player nowadays. Consistency, though, has been an issue: At past six majors, has one title and one runner-up showing — but also three first-round exits.

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KAROLINA PLISKOVA

Ranked: 7

Country: Czech Republic

Age: 26

2018 Match Record: 49-23

2018 Singles Titles: 2

Career Singles Titles: 12

Grand Slam Singles Titles: 0 — Best: RU, U.S. Open (2016)

Last 5 Australian Opens: 2018-QF, 2017-QF, 2016-3rd, 2015-3rd, 2014-2nd

Aces: Topped tour in match wins last season. ... Ranked No. 2 in aces with 393. ... Won hard-court tuneup title in Brisbane to open 2019.

Topspin: Superb serve helped her with steady progress in Melbourne; now it might be time to for a repeat run to the last weekend at a hard-court major, something she did in New York a little more than two years ago.

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PETRA KVITOVA

Ranked: 8

Country: Czech Republic

Age: 28

2018 Match Record: 47-17

2018 Singles Titles: 5

Career Singles Titles: 25

Grand Slam Singles Titles: 2 — Wimbledon (2011, 2014)

Last 5 Australian Opens: 2018-1st, 2017-DNP, 2016-2nd, 2015-3rd, 2014-1st

Aces: Led the tour in titles last season; only woman to win trophies on three surfaces (hard, clay, grass).

Topspin: Hasn't been past the third round in Melbourne since reaching the semifinals for the only time way back in 2012. If the courts are playing fast, that'll be to her advantage.

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ARYNA SABALENKA

Ranked: 11

Country: Belarus

Age: 20

2018 Match Record: 46-22

2018 Singles Titles: 2

Career Singles Titles: 3

Grand Slam Singles Titles: 0 — Best: 4th, U.S. Open (2018)

Last 5 Australian Opens: 2018-1st, 2017-DNP, 2016-DNP, 2015-DNP, 2014-DNP

Aces: Opened season by winning title at Shenzhen, China. ... Went 21-8 in 3-setters last year, the most such wins on tour.

Topspin: Huge serve, groundstrokes quickly turned her into someone to keep an eye on as she quickly rose in rankings after beginning 2018 at No. 78. ... Australian Open will mark only her sixth career major appearance.

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ASHLEIGH BARTY

Ranked: 15

Country: Australia

Age: 22

2018 Match Record: 46-19

2018 Singles Titles: 2

Career Singles Titles: 3

Grand Slam Singles Titles: 0 — Best: 4th, U.S. Open (2018)

Last 5 Australian Opens: 2018-3rd, 2017-3rd, 2016-DNP, 2015-DNP, 2014-1st

Aces: Was No. 1 on tour last season in percentage of service points won, at 63.5. ... Was No. 4 in aces, with 297.

Topspin: An emerging talent who could give the home fans something to get excited about. ... Her journey to the top 20 included a stint playing cricket during an absence of nearly two years from the WTA after the 2014 U.S. Open.

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SERENA WILLIAMS

Ranked: 16

Country: United States

Age: 37

2018 Match Record: 18-6

2018 Singles Titles: 0

Career Singles Titles: 72

Grand Slam Singles Titles: 23 — Australian Open (2003, 2005, 2007, 2009, 2010, 2015, 2017), French Open (2002, 2013, 2015), Wimbledon (2002, 2003, 2009, 2010, 2012, 2015, 2016), U.S. Open (1999, 2002, 2008, 2012, 2013, 2014)

Last 5 Australian Opens: 2018-DNP, 2017-W, 2016-RU, 2015-W, 2014-4th

Aces: Hasn't won a title of any sort in two years, when she picked up No. 7 in Melbourne while pregnant. That also gave her 23 majors in all, a record for the professional era and one shy of Margaret Court's all-time record.

Topspin: After taking time off to have a baby, and dealing with a health scare during childbirth, Williams reached two Slam finals in 2018. No one should be surprised if she adds another trophy to her collection sooner rather than later.

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