The former France international appeared over 100 times for the Blaugrana between 2004 and 2007 before his coach at the time, Frank Rijkaard, replaced him with the Liga star.
"In January 2006, coach Frank Rijkaard told me: ‘Ludo, I want to see Messi more on the pitch from now on, he will play more,'" the 36-year-old told Le Parisien. "I understood he was the future. It was almost an honor for me to make way for him."
Giuly also stressed that key aspects were already present in Messi's game when he arrived in Spain as a teenager.
"He's a phenomenon. He already had his famous hooks, his liveliness and his inimitable style [when arrived at Barcelona]," he explained. "I thought it had to be judged over time. Many promising young people around 16 years old then disappear, there were plenty."
Giuly is chasing the Europa League places in Ligue 1 with his current club Lorient, as the club sits eighth, six points off fourth place.