It was the 71st-ranked Andujar's third career title, all on clay courts. He also won at Casablanca, Morocco, in 2011 and 2012.
Andujar got the only break in the first set to take a 5-3 lead and then held serve to close out the set.
Monaco, ranked No. 105 two years after being in the top 10, jumped out to a 3-0 lead in the second and served for the set up 5-3.
But Andujar reeled off four straight games, clinching the match by holding serve at love.