Karolína Plíšková of the Czech Republic in the first match of the day.
The first match was an all Czech affair, with Plíšková facing off against world #11, Lucie Šafářová.
World #14 Plíšková with a powerful forehand.
Left-handed Šafářová sendig the ball flying back to Plíšková.
1.86m (6 ft 1) Plíšková about to serve at the end of the first set.
Šafářová with a two-handed backhand. She handily won the first set, 6-3.
Plíšková fighting back in the second set.
And Šafářová rising to the challenge.
Plíšková gaining confidence after making up lost ground in the second set.
And Šafářová making a fightback.
After a tough second set, Plíšková prevailed, winning 7-6.
Šafářová serving from the south end fo the court in the third set.
Plíšková giving it all.
Šafářová expressing her frustration with the umpire.
Plíšková going deep to keep the pressure on Šafářová.
Shaking at hands at the end, with Plíšková winning 3-6, 6-7, 6-1.
Venezuelan-Spanish player, Garbiñe Muguruza in the second match of the day.
Up against Muguruza was Carla Suárez Navarro of Spain, the current world number #12.
1.82 m (6 ft) Muguruza firing the ball back down to the south end of the court.
Navarro making a dash to meet the ball across the court.
The current world #19 sending the ball flying.
Navarro keeping up the pressure on Muguruza, and won a hard fought first set, 7-6.
Muguruza stepping up her game in the second set.
And Navarro trying to keep up.
Muguruza with a flying backhand. She won the second set, 6-3.
And dominated in the third set.
Despite being 10 cm shorter, Navarro was still a match for her taller opponent.
Keeping up the pressure until the very end.
And winning the match, 6-7, 6-3, 6-3.
Ekaterina Makarova of Russia in the third quarter-final match of the day.
Facing off against Makarova was #1 seed, Simona Halep of Romania.
Makarova, the current world #9, firing back with a powerful backhand.
And Halep with an equally strong forehand. Halep won the first set, 6-3.
Makarova ratcheting up the action in the second set.
World #3 Halep struggling to cope with the big fight back from Makarova.
World #9 Makarova with another big backhand, and easily winning the second set, 6-1.
Halep showing the form that got her to the finals of last years French open.
Makarova digging deep for the battle during the final set.
Halep at the end of a very close match, winning, 6-3, 1-6, 7-5.
Wild card entry, 33 year old Flavia Pennetta of Italy.
Up against Pennetta in the final match of the day, Caroline Wozniacki of Denmark.
Pennetta giving up a tough fight at the south end of the court.
And Wozniacki with a flying forehand, winning a tough first set, 7-5.
Pennetta with a big backhand, struggling with the relentless Wozniacki.
Wozniacki dominating the second set.
Pennetta and Wozniacki embracing at the end of the match, with Wozniacki on to the semi-finals winning with 7-5, 6-0.