The Senegalese international has been a revelation since his switch to the Tyneside club on a free in the summer, scoring fifteen times in the Premier League so far this term.
However, he has been the subject of transfer rumours since it was revealed that there is a minimum fee release clause in the Magpies' contract, but Best is sure the forward is happy at United.
"He has been unbelievable - the stats show that," said Best.
"I think it is only Robin Van Persie that has scored more [this season].
"He loves it here. He is playing good football and he has found his feet. We are a massive club. We've got big new sponsors in, which shows how big we are."
Ba is currently with the Senegal squad ahead of the African Cup of Nations.