STOCKHOLM — Grigor Dimitrov of Bulgaria advanced to the semifinals of the Stockholm Open by beating Kevin Anderson of South Africa 7-6 (3), 5-7, 6-2 on Friday.

In the semifinals he will face Olympic silver medallist Juan Martin del Potro of Argentina, who withstood 12 aces to beat Croatian veteran Ivo Karlovic 6-3, 6-4.

Fourth-seeded Alexander Zverev beat German countryman Tobias Kamke 6-3, 7-6 (5) to set up a semifinal match against sixth-seeded American Jack Sock.

Sock won 6-4, 6-4 against Portugal's Gastao Elias, who had beaten top-seeded Gael Monfils in the second round.