The 22-year-old qualifier Beatriz Haddad Maia has scored her most significant wins in a career so far, toppling the top seed and the world no. 4 Sloane Stephens 6-3, 6-3 in an hour and 23 minutes. Haddad Maia played on a very high level, facing just two break points and pushing Stephens to the limits on the return, stealing half of the points on the American's serve and breaking her four times from seven chances to control the scoreboard.
They traded breaks in the opening games of the match and Beatriz added another one at 3-2, breaking at love to grab the lead that she carried home for a 6-3. The Brazilian never looked back, defending her initial shot nicely and breaking the pale Stephens in games three and nine to seal the deal and celebrate a huge win that keeps her on the title course.
Yafan Wang had to play just five games before Monica Puig retired 30 minutes since the start of the match, saving all three break points and moving ahead with a break in game two. The 3rd seed Donna Vekic scored another solid win, beating a qualifier Christina McHale 6-4, 7-5 in an hour and 49 minutes despite a lot of problems on serve.
McHale broke her five times although that wasn't enough at least for a set, dropping 54% of the points in her games and suffering seven breaks to send Donna over the top. It was a shaky start for both players, with five breaks in the opening five games, three for Vekic who forged a 4-2 advantage.
McHale broke back in game eight to level the score at 4-4 before she squandered game points in the game that followed, allowing Donna to break her and close the set on own serve a few minutes later. The American opened a 5-2 lead in set number two with a double break, wasting two set points on serve at 5-3 and another one on the return in game ten, spending them all to keep Donna in the set.
The Croat used this momentum to secure a break at love in game 11, crossing the finish line with a hold at 30 to move into the quarter-final. The 8th seed Johanna Konta has been in great form in Acapulco so far, ousting a qualifier Varvara Flink 6-4, 6-1 in an hour and 21 minutes, saving four out of five break points and conquering more than half of the return points for five breaks to have the upper hand all the time and race into the last eight.
Bianca Andreescu defeated the 4th seed Mihaela Buzarnescu 6-2, 7-5 while Sofia Kenin advanced when Katie Boulter was forced to retire at 4-6, 1-4 after 71 minutes. Victoria Azarenka delivered another rock-solid performance to topple Tatjana Maria 6-2, 6-1 in an hour and 24 minutes, losing serve once and dominating on the return to break the German six times and make herself a title contender if she keeps this level in the rest of the week.