Argentine international Messi is Barca's top goalscorer this season, with eight in La Liga, and he has already scored four times in the Champions League as well.
Messi joined Barcelona as a 12-year-old and Alexanco says the club could see from the start they had a special talent on their hands.
"Since he arrived at Barcelona at such a young age, we saw quickly that he had some very special qualities," said Alexanco.
"The qualities that he had then have now converted him into a unique player for his age.
"Watching him play now, it is of great satisfaction to us that he came from the academy of FC Barcelona.
"Examples such as him serve to motivate us even more, if possible, to work even harder at what we do."
Messi finished second in the 2007 Fifa World Player of the Year award, behind Brazilian Kaka and just ahead of Portugal and Manchester United winger Cristiano Ronaldo.
Alexanco translated from Spanish by Dominic Stevenson