Monica Niculescu missed out on a place in the quarter-finals of the Bucharest Open in her homeland when the fifth seed was beaten by Polona Hercog on Wednesday.

Niculescu reached the semi-finals of the inaugural WTA International clay-court tournament in the Romanian capital two years ago, but there will be no repeat this week after she went down 6-4 6-3 to the unseeded Hercog.

Hercog, 31 places below the 53-ranked Niculescu, lost to Alize Cornet in the first round of Wimbledon, but has made an encouraging response on clay.

The Slovenian grasped six of her eight break-point opportunities to set up a last-eight encounter with fourth seed Laura Siegemund.

German Siegemund needed only an hour and 21 minutes to beat qualifier Misa Eguchi of Japan 6-4 6-1.

American Vania King sent eighth seed Cagla Buyukakcay packing, dominating a deciding final set to win 7-6 (7-5) 4-6 6-1 and seal a meeting with Pauline Parmentier, conqueror of Aliaksandra Sasnovich.