Messi scored a brace as Barca kept the pressure on LaLiga leaders Real Madrid with a 4-2 win over Valencia on Monday (AEDT).
The Argentina star is top of the league's goalscoring charts with 25, putting together yet another phenomenal season.
Pique said he had become used to such displays from Messi, but he still lauded the 29-year-old.
"We are looking at the best player in history," Pique said, via the club's website.
"We have become used to this and we think it's normal, but we know that when he stops playing these things will be difficult to repeat."
Luis Suarez and Andre Gomes were also on the scoresheet for Barca, who played the second half against 10 men after Eliaquim Mangala saw red.
Pique remains upbeat about his side's chances of winning the league, although rivals Madrid have a two-point cushion and game in hand.
"I see La Liga as very possible," he said.
"There are many games to go and the difference between the leaders is very small."