Felix Mantilla defeated Roger Federer to become the first unseeded player to win in Rome since the Open Era began in 1968.
Reigning champion and ninth seed Juan Ignacio Chela was knocked out in the first round of the Estoril Open.
The world number one went down to Spain's Albert Costa in the second round of the Rome Masters.
The top seed was dumped out of the Barcelona Open by Argentine Jose Acasuso in straight sets.
The Briton he lost in the third round to slow court specialist Mariano Zabaleta.
The former world No. 1 reached the semi-finals of the Bellsouth Open at home in Chile.