PROMISING Japanese teenager Sara Saito is through to the quarter finals on WTA debut in her home tournament. The 18-year-old and former junior world number two upset talented fifth seed Elina Avanesyan to book her place in the last eight of the WTA Tour Japan Open.

Saito had to work hard early, saving two set points before putting away the hard-hitting Avanesyan to take out the opening set in a tiebreaker, before winning overall 7-6 6-4 in an hour and 56 minutes. While Saito might not be able to match the power of Avanesyan – who switched allegiances from Russia to Armenia this year – she is crafty and the wildcard showed that throughout the Round of 16 Center Court bout.

Saito only served the one ace for six double faults, but capitalised on two thirds of her first serve points off a 60 per cent clip. She was also able to create 14 break point opportunities – the same as Avanesyan did to her, but broke six times to five. While Saito is one to feed off the opposition’s power and redirect with well-angled shots, Avanesyan is the perfect player to do that do given her natural aggression and willingness to get involved in groundstroke rallies.

There was not much between the two players with Saito able to get more aggressive off the Armenian’s serve, to not up the first Top 50 win of her career. She joined 20-year-old Aoi Ito in the quarter finals after her compatriot upset Elisabetta Cocciaretto yesterday.

Incredibly Osaka has provided a remarkable amount of upsets, with just one of the eight seeds making the final eight, seventh seeded Frenchwoman Diane Parry. She booked her place with a 6-4 6-2 triumph of Greet Minnen in an hour and 25 minutes, while Minnen’s counterpart in Elise Mertens had to retire midway through the third set against Australian qualifier Kimberly Birrell, Saito’s next opponent.

Ningbo Open | Ningbo, China – WTA 500

There were no such upsets in Ningbo as the four top ranked players in action on Thursday marched through to the quarter finals. Number one seed Beatriz Haddad Maia won 7-6 7-5 against Katie Boulter in what was the closest match of the day. Barbora Krejcikova also had to work hard against Ye-Xin Ma before getting up 7-6 6-3, as she and her countrywoman Karolina Muchova both escaped lucky loser bouts. In the other match, Anna Kalinskaya defeated Yue Yuan, 6-3 6-3.

Nordic Open | Stockholm, Sweden – ATP 250

It was a throwback to simpler times in Stockholm on Thursday as veteran Stan Wawrinka wound back the clock to book a spot in the quarter finals. He fought off Spaniard Alejandro Davidovich Fokina in two hours and 12 minutes, 6-4 3-6 7-5, joining fellow veteran Grigor Dimitrov in the last eight after the 33-year-old knocked off Quentin Halys. Russian Andrey Rublev and Serbian Miomir Kecmanovic also won through to the quarter finals of the Nordic Open.

European Open | Antwerp, Belgium – ATP 250

Home fans were up and about in Antwerp as local chance Zizou Bergs upset Argentinian Sebastian Baez in straight sets, winning 6-3 6-4 across 93 minutes in the Round of 16. Bergs joined another surprise packet in American Marcos Giron to reach the quarter finals after he held off Frenchman Arthur Rinderknech in two tiebreakers. Greek talent Stefanos Tsitsipas found some form by edging out Brazilian qualifier Thiago Seyboth Wild in three sets, while Czech Jiri Lehecka was too good for German Daniel Altmaier.

Almaty Open | Almaty, Kazakhstan – ATP 250

Number one seed Frances Tiafoe had a scare against British qualifier Daniel Evans, with his opponent working Tiafoe over in Almaty. Evans won the first set 12-10 in the tiebreaker, before Tiafoe kept his hopes alive with a 7-4 second set tiebreaker. After two hours and 39 minutes, he finally shrugged off the former Top 30 player in two hours and 39 minutes. He made the quarter finals alongside Russian Karen Khachanov and Australian qualifier Aleksandar Vukic, while Shanghai semi-finalist Tomas Machac was forced to retire after just 17 minutes against Kazakh wildcard Beibit Zhukayev.