Moya, who won the first of his 18 ATP singles titles at the same event 10 years ago, needed only one hour 12 minutes to dispatch Argentina's Juan Monaco 6-1, 6-2.
The Spaniard now plays Mariano Puerta, another Argentine, in the quarter-finals.
Canas, who enjoyed the best season of his career last year by claiming three titles, fell 6-4 6-3 to Spain's Alberto Martin.
The Argentine's frustration got the better of him at the end of the first set when he was given an official warning for twice throwing his racket to the ground.
