Nikolay Davydenko advanced to the quarterfinals of the Nice Open on Wednesday with a hard-fought win over Denis Istomin of Uzbekistan.
Davydenko, the Russian No. 3 and world No. 53, beat the 80th-ranked Uzbek 6-4, 1-6, 6-3 to set up a quarterfinal against top seed John Isner of the United States or Belgium's Xavier Malisse.
The €400,000 clay court event is the last second-tier warm-up for the French Open, which starts Monday.
Four-time Grand Slam semifinalist Davydenko has had an erratic season so far, slipping 12 places from his 2011 season-ending ranking of 41.
