Walsh hit a nine-darter in the practice room earlier in the day, but he was unable to transfer that form onto the stage, where he was beaten by three sets to one.
He looked poised to win the opening set until Komula checked out 126 to level at 2-2 before kicking off the deciding leg with a 180.
Komula broke Walsh's throw with a double three to snatch the first set. He then claimed the second 3-1 to move 2-0 ahead.
The Englishman took out finishes of 118 and 121 to win the third 3-2, but Komula converted his seventh match dart to win the fourth by the same scoreline.
Walsh entered the tournament as the 29th seed, but he will now drop out of the world's top 32 players, meaning that he is likely to get significantly tougher first-round draws in future events.