weeks later, a resurgent Lučić-Baroni made major waves at the US Open. She defeated No. 25 seed Garbiñe Muguruza in the first round, and Shahar Pe'er in the second round to gain a berth in the third round for the first time since 1998. She then pulled off a huge upset, stunning second-seed Simona Halep in straight sets to win a spot in the round of 16—the best result of her career at this tournament, and her best showing at a Grand Slam since reaching the semifinals at Wimbledon in 1999. She went on to lose this round to 13th seed Sara Errani in three sets. However, only two weeks later, she entered the Quebec City event and reached the singles final, where she pulled off another major upset by beating Venus Williams on 14 September, setting a record for the longest gap between titles in WTA history, as her previous win happened 16 years and four months earlier at the 1998 Bol Ladies Open. In addition, paired with Czech player Lucie Hradecká, she won the doubles final of the tournament on the same day. 2015–16 In 2015, Lučić-Baroni had a second consecutive finish in the top 100 of the WTA rankings, ending the season ranked No. 67. Her best performance was reaching the semifinals of Quebec City. In 2016, she reached the final of the Strasbourg event, where she lost in straight sets to Caroline Garcia. 2017: Return to a Grand Slam semifinal and career-high ranking Mirjana entered the Australian Open ranked 79 in the world. In the first round, she beat Wang Qiang in three sets to advance into the second round where she upset the third-seed Agnieszka Radwańska in straight sets. In the third round she defeated Maria Sakkari in three sets. In the fourth round, she defeated qualifier Jennifer Brady in straight sets to advance to the quarterfinals where she pulled another major upset, beating Karolína Plíšková, a heavy favorite to win the tournament in three tight sets where she made her first Australian Open semifinals and her first semifinal appearance since she did so in the 1999 Wimbledon Championships 18 years ago. She then proceeded to lose in two sets against six-time Australian Open champion and No. 2 seed Serena Williams. She reached her highest ranking of No. 29 on 30 January, eclipsing her previous best of No. 32 set in May 1998. On 1