EXCLUSIVE By Adrian Boullosa
The 28-year-old inspired the club to the treble last season as he did six years ago during Pep Guardiola's first season in charge, but Carrasco believes he is now a more all-round weapon in attack.
"This Leo Messi is more complete," he told Goal.
"He can hurt you 40 metres away from goal, not because he takes the ball and starts dribbling past opponents, but because on top of that he can also create the definitive goal chance.
"The best player in the world, ahead of my precious [Andres] Iniesta, [Toni] Kroos and Isco, who are players that make the final assist, is Leo Messi. I haven't seen anything like him."
Messi initially struggled to find his best form in the first half of last season but excelled in the second half of the campaign.
Carrasco believes it merely took time for the Argentina international to find his feet again after a long year that saw him reach the World Cup final with his country.
"In the moment he found himself good physically and mentally, he tried to bring the team together, everybody joined him and from there all talents became stronger," said the 56-year-old.
"The god of football started playing, he is unstoppable when he starts playing. If you think otherwise, ask [Jerome] Boateng or all those fantastic players that face him.
"Barcelona expected good things last season, but not the treble. Matching the magical season of 2009 seemed almost impossible. Messi was the cornerstone of that success."
Carrasco claimed 10 major trophies during more than 300 appearances for Barcelona, including the Liga title in 1985.
He also reached the final of the European Championship in 1984, where Spain were beaten by host nation France and the inspirational Michel Platini.