Juan Martin del Potro downs Ivo Karlovic to reach semi-final in Stockholm

Having beaten John Isner in round one, Del Potro toppled another of the tour's giants, Ivo Karlovic, 6-3 6-4 in the last eight.

"I was expecting a tie-break in this match," said Del Potro on atpworldtour.com. "But I'm happy to get the rest for tomorrow when I play Grigor."

Second seed Dimitrov needed three sets to overcome South Africa's Kevin Anderson 7-6 (7/3) 5-7 6-2 while fourth seed Alexander Zverev will play Jack Sock in the other semi-final.

David Goffin continued his push for a place at the ATP World Tour Finals in London by coming from a set down to defeat Marius Copil in the quarter-finals of the European Open in Antwerp.

Goffin eventually won 5-7 6-1 6-3 and next faces Argentina's Diego Schwartzman.

Britain's Kyle Edmund reached his first ATP Tour semi-final with a 6-3 6-4 victory over Andreas Seppi and will play third seed Richard Gasquet, who he beat in the opening round of the US Open.

At the Kremlin Cup in Moscow, Italy's Fabio Fognini extended his record to 8-0 against Albert Ramos-Vinolas with a 6-2 6-2 win over the second seed.

Fognini next meets third seed Philipp Kohlschreiber, while the other semi-final pits Stephane Robert against Pablo Carreno Busta.