The diminutive Barcelona forward made history once again on Wednesday night by becoming the first man to score five goals in a single Champions League during his side's 7-1 victory over Bayer Leverkusen at Camp Nou.
Sabella freely admits that he has run out of superlatives for the player he feels must now be regarded as the finest in the history of the game.
"As well as playing a great team, Messi has so much ability that he doesn't even need a chance," he told Fox Sports. "For him, we must invent a new adjective."
Indeed, Sabella is in no doubt that Messi has no equal and does not agree with the view that the Rosario native must prove himself on the game's biggest stage in order to be universally accepted as the greatest player of all time.
"I do not see it as crucial that Messi wins a World Cup to be the best in the world," he argued.
"But what he's doing is unique. He doesn't seem to me to be comparable to any of the others.
"There was the era of [Alfredo] Di Stefano, the era of Pele and the era of [Diego] Maradona. But now is Messi era. This is the reign of Messi.
"And I am pleased that I will now be able to say that I coached him."
However, Sabella concedes that his job is to ensure that Messi has the necessary support and assistance to reproduce his club form at international level.
"We have to make sure we get the best out of him," he admitted. "Barcelona are a unique team and if they were a national team, they would be the best in the world, and in with a great chance of winning the World Cup.
"We, in the national team, have to make sure that Messi is well supplied, creating options for him so that others can carry the side. It is a difficult task but that is the way to look at it."
Messi returns to La Liga action with Barcelona this weekend in their clash with Racing.
Since November, Goal.com has been publishing exclusive extracts from Graham Hunter's highly-anticipated new book, 'Barca: The Making of the Greatest Team in the World'. The very last extract, which was published last Friday, looks at Andres Iniesta's risky return from injury in the 2009 Champions League Final and how he was described by Wayne Rooney as the 'best midfielder in the world'. Don't miss it!