Unseeded Mayar Sherif and 31st seed Irina-Camelia Begu pulled off upsets to advance to the quarterfinals of the Mutua Madrid Open on Monday in Spain. Sherif, the Egyptian who is ranked 59th in the world, knocked off the tournament's 24th seed, Elise Mertens of Belgium, 6-4, 0-6, 6-4. Begu, of Romania, ousted 14th-seeded Liudmila Samsonova of Russia in straight sets, 6-4, 6-4. Sherif saved 52.9 percent of her break points (9 of 17) and converted 58.3 percent of break points (7 of 12) against Mertens. She was the only unseeded player to make the quarterfinals, thanks in part to building momentum in the earlier rounds. One of those wins was 7-6 (2), 6-3 against No. 5 seed Caroline Garcia, who had beaten Sherif 6-0, 6-4 a few months ago in Monterrey, Mexico. "Last week helped me find a match rhythm," Sherif said. "Even though I was playing lower-level matches, it gave me confidence by winning. I lost the first set 6-0 (in Mexico), but I played better after that. "This tournament, I was ready for it. I had the mental chip, 'OK, I lost the last time and I'm going to try to play with more confidence.' I believed that I can beat her." Begu fell behind 3-0 in the first set but broke Samsonova's serve twice in winning five straight games. The Russian fended off a set point in winning on serve to pull within 5-4, and she also held off another set point with Begu on serve, but the Romanian won her next set point. The second set was close throughout, until Begu, leading 6-5, didn't lose a point in serving out the match. Elsewhere, 12th-seeded Veronika Kudermetova of Russia eliminated eighth-seeded countrywoman Daria Kasatkina, 7-5, 1-6, 7-6 (2). Kudermetova next will face the third seed, Jessica Pegula of the US, who defeated No. 18 seed Martina Trevisan of Italy 6-3, 2-6, 6-3. Iga Swiatek, the world's top player and the top seed, survived a challenge from the 16th seed, Ekaterina Alexandrova of Russia, 6-4, 6-7 (3), 6-3. The match lasted nearly 2 1/2 hours and put Swiatek in the quarterfinals of the tourney for the first time. "That wasn't an easy match. In the second set, I had the lead and I lost it, so for sure it wasn't easy, but I'm pretty happy that I could reset in the third. I was ready, I got a break pretty early, so overall I'm happy with the performance," Swiatek said. Winning in straight sets were the second seed, Aryna Sabalenka of Belarus; Greece's Maria Sakkari, the ninth seed; and 27th-seeded Petra Martic of Croatia.