The 21-year-old Martin, who last year became the first amateur to win an event on the European tour with his victory at the Portuguese Open, had eight birdies. He is now a professional.
Bourdy also had eight birdies on the Oitavos Dunes course in a span of 11 holes beginning with the sixth.
The course record of 64 had been matched earlier in the day by Gonzalo Fernandez-Castano of Spain. Fernandez-Castano was tied for third with Jose Manuel Lara of Spain and Swedens Michael Jonzon.