The 22-year-old Brazil forward is currently joint top scorer in his first World Cup along with Messi and Germany's Thomas Mueller on four goals from three games.
Messi, playing in his third World Cup, has almost single-handedly carried title contenders Argentina into the second round by scoring four of their six goals, including a stoppage-time winner against Iran.
"Messi is an excellent player, a star, one of the best players in the world," Scolari told reporters on Friday when asked if he shared former Brazil striker Ronaldo's view that Messi was the best.
"Naturally any club, national team or backyard game will want him around. This is Ronaldo's opinion and we have to respect it.
"He is one of the best. He is a player of a lot, alooot of quality," he said, dragging out the word.
Scolari, however, said he would announce his verdict once both players had finished their careers.
The two South American nations are depending heavily on their prolific strikers.
There have, however, been growing concerns over the past weeks regarding Argentina's over-dependence on the 27-year-old, and comparisons with former Argentina captain Diego Maradona and his sensational 1986 World Cup when he led them to their second title.
"My personal opinion, I will tell you in 10-15 years. Now I don't have to tell you anything," said Scolari.
Neymar, who had a less than successful first season at Barcelona, got the backing of Brazil captain Thiago Silva, who said the player would soon reach the dizzying heights of Messi.
"Messi is one of the best strikers. But I think Neymar is in a crescendo and depending where we are at end of the World Cup he will be considered one of the best player or the best player in the world," Thiago said.
"He is going to get there where Messi is today. Messi is undoubtedly one of the best but I am sure Neymar will get there."