The WTA Top 20 remains the same as the first Grand Slam of the year begins - but Simona Halep moves up one spot in the rankings following her run to the Adelaide International quarterfinals.

Defending Australian Open champion Naomi Osaka drops down to World No.4 as the Romanian edges up one place to World No.3 after defeating Ajla Tomljanovic 6-4, 7-5 in the Round of 16 before falling to Aryna Sabalenka.

Here are some of the week's other big rankings movers: 

Dayana Yastremska (+3, No.24 to No.21) - The Ukrainian teenager didn't drop a set en route to the Adelaide final, knocking out two seeds in Angelique Kerber (6-3, 2-0 ret.) and Aryna Sabalenka, 6-4, 7-6(4), along the way. She finished the week as runner-up to World No.1 Ashleigh Barty.

Danielle Collins (+2, No.27 to No.25) - The American had a fantastic time in Australia last year, and prepared for the 2020 edition in fine style. In Adelaide, she beat Belinda Bencic (6-3, 6-1) as well as compatriot Sofia Kenin (6-3, 6-1) having got past Aliaksandra Sasnovich in the first round - all without dropping a set.

Elena Rybakina (+4, No.30 to No.26) - There's almost no stopping the Kazakh so far this year. After her run to the final in Shenzhen, she followed that up with lifting the Hobart International trophy - beating Zhang Shuai 7-6(7), 6-3 in the final, and adding the scalps of Tamara Zidansek, Alizé Cornet, Lizette Cabrera, and Heather Watson to her collection during the campaign.

2020 Hobart Highlights: Rybakina romps to second career title

Zhang Shuai (+5, No.40 to No.35) - After being knocked out of Shenzhen in the Round of 16, Zhang bounced back to reach the final in Hobart, beating Kirsten Flipkens, Kateryna Kozlova, Lauren Davis, and fifth seed Veronika Kudermetova along the way.

Bernarda Pera (+5, No.70 to No.65) - The American enjoyed a fine week in Adelaide, coming through qualifying with a straight-sets win over Britain's Katie Boulter then a tight three-set tussle with Coco Vandeweghe, and defeating Barbora Strycova in the first round of the main draw.

Heather Watson (+26, No.101 to No.75) - The British star enjoyed another great start to the Australian swing, making a run to the Hobart semifinals - a tournament where she was champion in 2015. This year she added Elise Mertens to her list of scalps, defeating her 6-7(5), 6-4, 7-5 in the quarterfinals.

Ons Jabeur (+7, No.85 to No.78) - A fight through qualifying in Hobart and then a 6-4, 6-1 win against Anna Blinkova in the first round set the Tunisian up for a rankings rise.

Kateryna Kozlova (+8, No.91 to No.83) - Another qualifier in Hobart, the Ukrainian beat Sara Sorribes Tormo 6-2, 6-1 in the first round before falling to eventual runner-up Zhang Shuai in the Round of 16.