Eighth-seeded Nick Kyrgios has advanced to the semi-finals of the China Open in Beijing.

The Australian on Friday accounted for Steve Darcis 6-0 3-0, with the Belgian forced to retire with a neck strain. Darcis had received on-court treatment earlier in the match.

Kyrgios is set for a likely showdown in the last four with No.2 seed Alexander Zverev. The German will face young Russian Andrey Rublev in the remaining quarter-final.

Earlier, top-ranked Rafael Nadal joined Kyrgios in the semis, beating sixth-seeded John Isner 6-4 7-6 (7-0).

“In general terms, I think I played with not many mistakes,” Nadal said.

“I don’t remember a lot of mistakes. I went to the net very often. I think I did the things that I want to do, and I did it well, so very happy.”

The French and US open champion has won five titles this season and is closing in on the year-end No.1 ranking.

Nadal saved all three break points he faced against Isner.

The Spaniard will face third-seeded Bulgarian Grigor Dimitrov in the last four.

Dimitrov earlier defeated No.5 Roberto Bautista Agut 7-6 (7-5) 4-6 6-2.