Nikolay Davydenko overcame a stern challenge from Romania's Victor Hanescu to reach the semi-finals of the International German Open in Hamburg.

The Russian second seed, who is bidding for a first title of the season, came through a deciding set to defeat 11th seed Hanescu 6-3 4-6 6-3.

Davydenko will face sixth seed David Ferrer in the last four after the Spaniard eased past German wild card Simon Greul 6-2 6-3.

Uruguayan qualifier Pablo Cuevas claimed his third seeded scalp of the tournament, this time upsetting 14th seed Nicolas Almagro 6-2 6-4 to move within one win of a first ATP Tour final appearance.

The world number 107 will again be the underdog in the last four when he takes on France's 13th seed Paul-Henri Mathieu, who was leading 3-0 when quarter-final opponent Victor Troicki retired.