Barcelona forward Lionel Messi says he "never imagined" scoring over 400 goals in his remarkable career.

The four-time world player of the year, 27, passed the landmark with a brace in the Spanish side's 6-0 home win over Granada on Saturday.

The Argentina captain headed in his 400th goal for club and country and then stroked in his 401st late on.

"It's like Messi was touched by a magic wand," said Barcelona coach Luis Enrique.

"I don't think if we added together the goals we have scored on the playground it would reach 400," Enrique told journalists in his post-match news conference.

Messi has scored 359 goals for Barcelona since making his debut in 2004, plus 42 strikes for Argentina, in 506 career appearances.

He is already widely considered as one of the all-time greatest players after being instrumental in helping Barcelona win 21 trophies, including six La Ligas and three Champions Leagues, in the past decade.

He has also won a host of individual honours including four consecutive Ballon d'Ors, the trophy given to the world's best player, between 2009 and 2012.

"I never imagined I could achieve anything like this in my career," said Messi on his official Facebook page. 

"I'll continue working hard to reach more targets."

Messi also helped set up three goals against Granada as unbeaten Barca, who finished as runners-up last season, moved top of La Liga after six matches.