MEXICO CITY (AFP) - Women's tennis world No. 1 Angelique Kerber defeated defending champion Heather Watson 6-4, 6-4 on Friday to reach the semi-finals of the WTA tournament in Monterrey, Mexico.

The German saved all eight break points she faced in a gritty display against the Briton, setting up a semi-final clash with fourth-seeded Spaniard Carla Suarez Navarro, who was a 6-1, 6-1 winner over French seventh seed Alize Cornet.

"I think it was a good match, especially at the end," said Kerber, who made early breaks in each set stand up despite the pressure applied by Watson.

Three-time champion Anastasia Pavlyuchenkova, the second seed, battled through three sets to defeat fifth-seeded Hungarian Timea Babos 6-2, 3-6, 7-5.

The Russian needed almost two hours to turn back a late charge from Babos.

She had appeared to be cruising when she took the opening set in less than 20 minutes.

But the Hungarian grabbed a late break in the second set to force the third.

Babos earned the first break of the decisive set, and missed three chances to make it a double break before Pavlyuchenkova broke back to knot the set at 3-3, finally seizing her chance to close out the match on Babos' serve.

"I started to feel the tiredness a little bit - it's been a long and tough trip for me - but I just stayed calm anyhow," said Pavlyuchenkova, who lifted the trophy in Monterrey in 2010, 2011 and 2013.

"I just stayed calm and played every point and fought till the end," added the Russian, who next faces third-seeded Caroline Garcia. The Frenchwoman defeated American Julia Boserup 6-3, 6-2.