MIAMI, FL, USA -- Monday was a big day for Japan as Misaki Doi and Nao Hibino upset the top two seeds in the first round of qualifying at the Miami Open.
Former Top 30 player Doi needed nearly two and a half hours and had to save four match points spanning two sets before overcoming No.1 seed Anastasia Potapova of Russia, 3-6, 7-6(10), 7-6(2).
17-year-old Potapova, who reached two WTA singles finals last year, came all the way back from 1-5 down in the second set and held three match points in the second-set tiebreak, but Doi persevered to pull out that lengthy breaker.
Potapova then served for the match at 5-4 in the third set and held a fourth match point in that game, but Doi broke serve to level the match at 5-5, then dominated the decisive tiebreak.
Hibino also came back from a set down, eliminating No.2 seed and former Top 5 player Eugenie Bouchard of Canada, 4-6, 6-0, 6-4 in one hour and 46 minutes. Hibino fired four aces in the final set to close out the win, which is her fourth victory over Bouchard in the last year.
After Hibino raced through the second set in 25 minutes, Bouchard broke the Japanese player's serve to open the decider and stayed up a break through 3-2. But Hibino broke the 2014 Wimbledon finalist to level the set at 3-3, and then broke serve in the final game of the match to claim the win and extend her undefeated record against Bouchard to 4-0.
Other high seeds made it through their opening matches. No.3 seed Dalila Jakupovic of Slovenia overcame France's Fiona Ferro, 1-6, 6-3, 6-2, and No.4 seed Viktorija Golubic of Switzerland advanced when India's Karman Thandi had to retire while trailing 6-0, 3-0.
No.7 seed Kaia Kanepi of Estonia, a former Top 15 player and a six-time Grand Slam quarterfinalist, also moved into the final qualifying round by easing past Spain's Paula Badosa Gibert, 6-3, 6-3, in 63 minutes.
No.10 seed Taylor Townsend of the United States survived a scare from 16-year-old Chinese wildcard Zheng Qinwen, ultimately prevailing 4-6, 7-5, 6-4 in two hours and 16 minutes. Zheng, ranked World No.801, led 5-1 in the second set and was up an early break in the third set before Townsend turned both of those sets around.
In an all-American match, Sachia Vickery upset No.5 seed Jennifer Brady, 2-6, 6-3, 6-2. Marie Bouzkova of the Czech Republic also claimed an upset, eliminating No.6 seed Katie Boulter of Great Britain, 6-4, 6-2. Crafty Romanian Monica Niculescu also took out a seed, defeating No.9 seed Lara Arruabarrena of Spain, 6-0, 2-6, 6-4.
No.21 seed Veronika Kudermetova, who beat Bouzkova to win the Guadalajara WTA 125K Series event last week, was not as fortunate, as the Russian fell to former Top 15 player Yanina Wickmayer of Belgium, 6-4, 6-2.