Robin Haase's ability to turn on the style at the Swiss Open continued as he overcame top seed David Goffin in THE quarter-final.

Goffin, who this month returned from an ankle injury that ruled him out of the grass-court season and is still searching for a third ATP World Tour title, was well off the pace as sixth-seed Haase wrapped up a 7-5 6-1 victory in just 81 minutes.

The Dutchman is a two-time losing finalist in the Alps, including 12 months ago to Feliciano Lopez, and will continue his bid to go one better against Yannick Hanfmann - who himself upset eighth seed Joao Sousa in a come-from-behind three-sets win.

On the other side of the draw, Roberto Bautista Agut lost just six points on his own serve en route to a dominant 6-3 6-4 beating of Denis Istomin and he faces Fabio Fognini in the semi-finals following the Italian's triumph over Ernests Gulbis after three sets.

At the German Tennis Championships, Karen Khachanov - who was the highest seed remaining in the draw at number three - slipped to a 7-5 3-6 6-4 last-eight loss to Federico Delbonis.

Awaiting in the last four is Delbonis' Argentine compatriot and 2014 champion Leonardo Mayer, who dispatched of Jiri Vesely 7-6 (7-4) 6-3.

There are no seeds left in the draw after Diego Schwartzman (6) was defeated by Florian Mayer, and Philipp Kohlschreiber's three-sets victory over Nicolas Kicker guarantees a German will be in the final.