MADRID -- A day after snapping her six-match losing streak in the first round of the Mutua Madrid Open, Egypt's Mayar Sherif played the best match of her season to defeat 25th seed Marta Kostyuk 6-2, 7-5 and advance to the third round. 

Sherif's back-to-back wins -- her first since July of 2023 -- earn her a shot at No.4 Elena Rybakina next. 

Sherif's victory was just one sign of a tough day for the top seeds in Madrid. Eight seeded players in the bottom half of the draw took an early second-round exit, highlighted by No.6 seed Zheng Qinwen. Putintseva led the Australian Open finalist 7-5, 2-0 when Zheng decided she could not continue the match due to a right thigh injury. 

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Putintseva will face American Caroline Dolehide in the third round. No.56 Dolehide rode the wave of upsets to her second Top 40 win of the season, besting No.30 seed Anhelina Kalinina 6-7(6), 6-2, 6-3. 

Ashlyn Krueger joined Dolehide in ousting a seed to earn a third-round berth. Making her tournament main-draw debut, the 19-year-old American overpowered 14th seed Ekaterina Alexandrova to win 6-3, 6-3.

Czech qualifier Sara Bejlek backed up her first-round win over Anna Blinkova to knock out Dubai finalist and 24th seed Anna Kalinskaya 6-1, 6-4. Bejlek, 18, will face Krueger in an all-teenage duel next with a first WTA 1000 Round of 16 on the line for each. 

As the day session neared its end, Romania's Jaqueline Cristian engineered a spirited effort to oust No.22 seed Barbora Krejcikova 2-6, 6-0, 6-2. After bouncing back to win six straight games in the second set, Cristian came from a break down in the second to win the last five games of the match. The victory is Cristian's third over a Top 30 opponent this season.

Highlights: Montgomery def. Boulter

American wild card Robin Montgomery also knocked out a seed. The 19-year-old left-hander fought back from a set and a break down to oust No.26 seed Katie Boulter 1-6, 6-3, 6-4, for her first Top 50 win since 2022. This week, World No.183 Montgomery has won back-to-back matches in a WTA main draw for the first time.