Tsonga, who will meet fellow countryman Gilles Simon in the last four, fought off five match points before claiming victory.

Simon overcame Argentina's Juan Martin del Potro, who won last week's Rotterdam Open, 6-4 6-3 with the second seed needing treatment on a thigh injury.

In the other semifinal, Russian qualifier Dmitry Tursonov will face top seed Tomas Berdych.

Tursunov saw off Gilles Muller of Luxembourg 7-6 1-6 7-5, while Czech star Berdych overcame Poland's Jerzy Janowicz 6-3 6-7 6-3.