Why must the alternative be hearing it? He's dealing with ghosts, and he's a mysterious ball of unknown origin and nature. Since the game has a supernatural nature, it's not unheard of for a character in a supernatural nature to have a supernatural ability. In this case, possibly a type of awareness.
It's utterly unreasonable to conclude that it's with smell he know where everything is.
All of this is irrelevant, of course, since we know for a fact that he can "sniff" the entire map. Down to every dot and cherry. Even if it was sense of smell, which nothing points towards aside from your "logic", he can smell the entire field, and I assure you that Link give out more smell than a ghost, and if he can smell a cherry the moment it spawn, then I'm rather confident smelling Link won't be a problem.
Even if he can't, Pacman can still turn on a dime, and Link can't be so close as to stab him without him sensing it before and turning around. Whatever the case, Link can't touch Pacman.
4. His chances of winning against Pacman, are about as great as the chances of Quan admitting his favoured/favourite character loses in a forum battle.
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"To all visitors from Transylvania looking for the head of Voivode Dracula: Yes, we have it. Yes, he's dead. No, you cannot see it. No, he will not return and invade you again. It has been over thirty years, please stop pestering us."
"To all visitors from Transylvania looking for the head of Voivode Dracula: Yes, we have it. Yes, he's dead. No, you cannot see it. No, he will not return and invade you again. It has been over thirty years, please stop pestering us."