#4 Caroline Wozniacki
The 28-year-old Dane began the year in the best possible way, winning her first ever Grand Slam title in Australia, defeating Simona Halep in the final of the tournament in three tight sets. By doing so, she was back at the world no. 1 spot for the first time since 2012. However, she lost that spot soon to Halep.
Apart from the Australian Open, she won titles at Eastbourne and China. She ended the year as the world no. 3.
#3 Naomi Osaka
The 21-year-old from Japan had a breakthrough year in 2018 and has surely made a name for herself. She began the year as the world no. 68 but consistent results throughout the year saw her rise up the rankings really quickly.
She won her first title at Indian Wells, defeating Daria Kasatkina in the final. However, the biggest title of her career came when she won the US Open, defeating her idol Serena Williams in the final which was marred by controversy.
She suffered from a few injuries towards the end of the season and was forced to retire in her final match of the WTA Finals against Kiki Bertens.
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