The 29-year-old German began his quest for a fourth consecutive title with an 11-9, 11-9, 11-8, 11-5 win over home favourite Lionel Weber before beating Greece's Panagiotis Gionis 11-7, 12-10, 7-11, 11-9, 13-11 in the quarter-finals.

Awaiting Ovtcharov in the semi-finals is Denmark’s Jonathan Groth, who defeated Russia’s Alexander Shibaev 9-11, 11-6, 11-6, 11-5, 12-10 in the last eight.

The other semi-final pits Belarus’ Vladimir Samsonov against Germany’s Timo Boll after both came through their quarter-final encounters.

Samsonov overcame Sweden’s Mattias Karlsson 11-9, 11-8, 11-7, 10-12, 14-12, while Boll beat fellow German Bastian Steger 11-7, 9-11, 11-5, 13-11, 11-6.

In the women’s singles event, top seed and defending champion Li Jie of The Netherlands defeated Germany’s Sabine Winter 11-5, 11-4, 10-12, 11-5, 11-8 in the quarter-finals.

It followed an 11-2, 11-7, 13-11, 11-6 victory over Russia’s Polina Mikhailova in the first round.

Next up for Li in the semi-finals is Romania’s Elizabeta Samara, who overcame Austria’s Liu Jia 11-4, 7-11, 11-3, 11-7, 13-11 in the last eight. 

Also through to the penultimate round is Samara’s compatriot Bernadette Szocs after she beat Hungary’s Georgina Póta 11-7, 11-6, 11-5, 12-10.

Her reward is a meeting with Sweden’s Matilda Ekholm, who booked her place in the semi-finals with an 11-5, 11-6, 11-7, 11-9 win over Austria’s Sofia Polcanova.

All semi-finals are scheduled to take place tomorrow and will be followed by the finals and the third-place play-offs.