With Poland winning the United Cup, Elina Svitolina winning the WTA Auckland title, and Aryna Sabalenka crushing opponents en route to a WTA Brisbane victory, week one of the tennis season is complete. There were a couple of moves in the WTA rankings, ahead of the Australian Open’s buildup and Jan. 18 opening day. LWOT highlights some of the biggest movers around the WTA Top 100 including Marta Kostyuk. In case you missed the tennis, we also have a quick list of some of the best matches of the week, played between Top 100 opponents.

Biggest Movers in the WTA Top 100 This Week – Week 1 

Madison Keys: -2: World No. 7 -> World No. 9 

Not a big move in the rankings, but Keys dropped crucial ranking points due to winning the WTA 500 Adelaide tournament in 2025. This year, she lost in the quarterfinals of the Brisbane tournament to Aryna Sabalenka. As a result, she won’t be a top eight seed for her title defense at Australian Open, meaning it’s possible she could face a player of the likes of Sabalenka or Swiatek by the fourth round. That could be troubling for Keys, who isn’t at her best right now. Or, after the American stunned Sabalenka and Swiatek during last year’s Australian Open, it could be a great setup for deja vu.

Marta Kostyuk: +6: World No. 26 -> World No. 20 

Kostyuk picked up just one Top 10 win over the course of 2025. This week alone in Brisbane, she took out three Top 10 opponents; her 6-4 6-3 upset over (then ranked) World No. 3 Amanda Anisimova was arguably the most impressive. The Ukranian revealed that she emphasized better fitness and a longer break over the tennis offseason, as she’s at her highest ranking since last year’s Australian Open.

Xinyu Wang: +14: World No. 57 -> World No. 43

After Wang defeated Alexandra Eala in a thrilling WTA Auckland semifinal on Saturday, the Chinese No. 2 is back in the Top 50 for the first time since a six-match losing streak last season plunged her ranking. Wang is still looking for her first WTA Tour title.

Daria Kasatkina: -8: World No. 40 ->World No. 48

A tough opening round loss in Brisbane dropped Kasatkina’s ranking to its lowest since early 2021. Now representing Australia, Kasatkina was candid about late season struggles and ended her 2025 early in October. Kasatkina also has some tricky Australian Open fourth round points to defend.

Ashlyn Krueger: -12: World No. 49 -> World No. 61

Krueger made both the quarterfinals of the WTA 500 Brisbane and Adelaide tournaments in 2025, though she lost in the first round of the Brisbane tournament this year and couldn’t reach the main draw of Adelaide. The American received some heightened attention last season, as her powerful serve led her to upset Elena Rybakina at the Miami Open.

Best Matches of the Week: 

Madison Keys d. Diana Shnaider 6-7 (5) 7-6 (5) 7-6 (4) – Brisbane Third Round

Mirra Andreeva d. Linda Noskova 5-7 6-4 7-5 – Brisbane Third Round

Elina Svitolina d. Sonay Kartal – 6-4 6-7 (4) 7-6 (5) – Auckland Quarterfinals

Xinyu Wang d. Alexandra Eala 5-7 7-5 6-4 – Auckland Semifinals

Belinda Bencic d. Elise Mertens 6-3 4-6 7-6 (0) – United Cup Semifinals

Upcoming Week 2 Predictions:

Hobart: WTA Day 1

Adelaide: WTA Day 1 #1, WTA Day 1 #2

Main Photo Credit: Geoff Burke-USA TODAY Sports