Rome, Italy -- (Sports Network) - Third-seeded Serbian Novak Djokovic and Swiss Stanislas Wawrinka advanced to the final of the $3.5 million Italian Masters Saturday after both their semifinal opponents retired.

Sixth-seeded American Andy Roddick retired with a back injury trailing 3-0 in the first set, sending Wawrinka to his sixth career final. The Swiss player became the first unseeded finalist since Felix Mantilla, who defeated Roger Federer in 2003.

Wawrinka's win over Roddick was his second straight upset of a seeded American, as he downed eighth-seeded James Blake to reach the semifinals of the clay-court tournament.

Djokovic, meanwhile, advanced after 27th-ranked Czech Radek Stepanek retired. Djokovic led 6-0, 1-0 when the Czech, who had upended world No. 1 Roger Federer in the quarterfinals, called it a day. The Serb is in search of his 10th career title, and his third of the year.

This week's winner will take home $558,000.