MADRID (AP) -- Top-seeded Angelique Kerber defeated Katerina Siniakova of the Czech Republic 6-2, 1-6, 7-5 to advance to the third round of the Madrid Open and regain the world No. 1 ranking on Monday.
Kerber overcame seven double faults and won the final four games to defeat the 37th-ranked Siniakova in just under two hours on the center court in Madrid.
Kerber will face Maria Sharapova or Eugenie Bouchard, who played late Monday.
Second-seeded Karolina Pliskova, ranked third in the world, lost to Anastasija Sevastova of Latvia 6-3, 6-3, ending her hopes of reaching No. 1 this week.
That meant Kerber was guaranteed to retake the top ranking from Serena Williams next week.
In the men's tournament, Tomas Berdych defeated Denis Istomin of Uzbekistan 6-4, 6-4, while Grigor Dimitrov of Bulgaria beat Philipp Kohlschreiber of Germany 7-6 (7), 6-4.