It was Cuevas' second semifinal of the year, having reached the final four at Vina del Mar, Chile, in February. The 107th-ranked Cuevas beat another seeded player in the third round, No. 8 Philipp Kohlschreiber.
Cuevas, whose biggest success so far was winning the French Open doubles title in 2008 with Luis Horna of Peru, will meet 13th-seeded Paul-Henri Mathieu of France. Mathieu advanced when Viktor Troicki retired with a foot injury while trailing 3-0.
After missing much of the first four months of the year with various injuries, Davydenko has reached his third semifinal of 2009. He is still without a title this year.
Ferrer, who is also looking for his first title of the year, has split the previous two matches against Davydenko. Cuevas and Mathieu have never played each other.