She continued having success in her next tournament, where she won the title in singles and reached semifinals in doubles in the 2009 Widjojo Soejono Semen Gresik Junior Championships.

The next week, Zhu won her first doubles title and also reached the semifinal in singles at the Solo Open International Junior Championships.

Toward the end of the year, she reached one singles final at the PHINMA International Juniors (week 2), where she lost, but won two doubles titles, at that tournament.

In January 2010, Zhu debuted at a junior Grand Slam tournament, playing at the Australian Open, where she was stopped in the third round by Kristýna Plíšková.

In August, she played her first Grand Slam qualifying; after defeating Giulia Gatto-Monticone and Arina Rodionova, she lost in the third round to Zheng Saisai.

Having entered the qualifying tournament, she defeated Wang Yafan, Raluca Olaru, and Elitsa Kostova for a spot in the main draw, where she subsequently recorded her first ever main-draw win on tour level by defeating Kristýna Plíšková in the first round, but was stopped in the second by Jana Čepelová.

Next week, she played her first Premier Mandatory tournament, in the main draw of the China Open where she defeated Anastasia Pavlyuchenkova in the first round, but lost to Simona Halep in the second.

At the Indian Wells Open, she reached the second round by defeating Francesca Schiavone after a controversial call from the umpire,[6][7] but then lost to Sara Errani.

Zhu made her major singles debut at Wimbledon, where she lost to Belarusian qualifier Aliaksandra Sasnovich in three sets.

At the Wuhan Open, she failed to qualify in singles, but reached the second round in doubles together with Han Xinyun, they lost to Bethanie Mattek-Sands and Lucie Šafářová.

In November, she reached her first $100k final in doubles at the Shenzhen Open, but lost with Han Xinyun against You Xiaodi and Nina Stojanović.

At the Dubai Championships, Zhu made one of her biggest wins, defeating reigning Doha champion Elise Mertens, but lost in the second round to Lesia Tsurenko.

[9] After losing six first-round matches, Zhu clinched her first singles victory at a Grand Slam tournament at the US Open, beating compatriot teenager Wang Xinyu in straight sets, before she lost to Madison Keys in the second round.

[11] In December, she won her first singles title on the WTA Challenger Tour in Seoul, defeating Kristina Mladenovic in the final.

[14] In Hua Hin, Thailand, she defeated seventh seed Wang Xinyu in the semifinals with whom she reached the doubles final at the same tournament.

[19] En route to the final, Zhu defeated Taylah Preston,[20] Linda Fruhvirtová,[21] Arina Rodionova,[22] and Wang Yafan, [23] all without dropping a set.