Nikolay Davydenko stood up to top seed John Isner to claim a 6-4 7-6 (7/4) victory and move through to the semi-finals of the Nice Open.
Despite Isner's 11 aces, the American's serve was broken in the first set and that solitary break proved enough for unseeded Russian Davydenko to cling on for victory in one hour and 41 minutes.
Former world number three Davydenko will face another American, Brian Baker, in the last four after the world number 216 continued his superb run by saving a match point en route to a 4-6 6-3 7-6 (7/4) win over Kazakhstan's Mikhail Kukushkin.
Second seed Gilles Simon made it safely through with a 7-5 6-0 win over Brazilian qualifier Thomaz Bellucci, and he will next face third-seeded Spaniard Nicolas Almagro, who beat Belgium's Steve Darcis 6-4 6-4.
