The 34-year-old netted all five goals in the victory in Pamplona, having helped Argentina win last weeks Finalisima over Italy 3-0 with two assists.
Messi’s latest heroics coincided with Nadal’s 14th title at Roland Garros on Sunday, beating Casper Ruud 6-3 6-3 6-0 in the final.
“I don’t know what else to say. It’s very difficult; it’s like Rafa Nadal, what are you going to say?,” Scaloni told TVP after the game.
“It is preferable that the journalists speak, that they speak. You have no words left to describe it, and above all, for everything it generates.”
Messi now has 86 goals in 114 appearances for Argentina, sitting 30 goals clear of the country’s next best scorer Gabriel Batistuta.
“He is something unique, and it is a pleasure to have him in this group,” Scaloni said.
“It is a pleasure to train him, the entire coaching staff. And it’s a pleasure his behaviour and how he toasts to his shirt. We only have words of thanks.
“I don’t think he’s just the heritage of Argentina; he’s the heritage of the world, of world football.
“The day he doesn’t play anymore, we are going to miss him.”
Messi led Argentina to a drought-breaking Copa America triumph last year and will be a key part of the side that chases their first World Cup title in 36 years later this year.