Canas, seeded No. 1, worked out a 7-6 (7-2), 6-3 quarterfinal victory over Hungary's Attila Savolt.
El Aynaoui, the second seed, saved three match points and rallied past French qualifier Paul-Henri Mathieu, 2-6, 6-4, 7-6 (7-3).
In Saturday's semifinals, Canas meets No. 5 Julien Boutter, who saved two match points to battle past fellow French qualifier Jean-Rene Lisnard, 3-6, 6-4, 7-6 (7-1). El Aynaoui faces unseeded Russian Mikhail Youzhny, who pulled away to beat France's Anthony Dupuis, 7-6 (7-5), 6-2.
Canas, who was forced to qualify after missing most of 2000 while recovering from surgery on his left wrist, did not drop a set in seven matches en route to winning his first career ATP title at Casablanca.
Despite having to contend with cool and windy conditions on Friday, Canas is enjoying defending an ATP title for the first time.
"I love playing in Casablanca," he said. "People are starting to get to know me and are cheering for me."
During the opening week of the 2002 campaign, Canas lifted the Tata Open hardcourt event trophy at Chennai, India to double his career haul.
Last year, the 30-year-old El Aynaoui lost a close match to eventual runner-up Tommy Robredo of Spain at the Complexe Al Amal, dropping the third-set tiebreaker, 9-7.
El Aynaoui reached his first career ATP final at Casablanca in 1993. He won his third career title at Doha in January, but has yet to capture his home tournament.