Albion held their lead until half-time, after Shane Long put them in front in the fourth minute, but second-half goals from Nicolas Anelka and Florent Malouda handed the Baggies their second loss of the season.
However, Hodgson insists that his players only have themselves to blame after losing in a similar fashion to champions Manchester United last Sunday.
"It's a little bit of deja vu because we didn't do badly against Manchester United," he told reporters.
"But you get punished at the very highest level for errors that you make, and unfortunately we made two very bad defensive errors down the left side that let them in and they took their chances.
"It could be due to fatigue but it could also be down to the fact that Chelsea's pressurizing was good in the second half and they have to take credit for that."
West Brom are looking to get off the mark when Stoke travel to the Hawthorns next weekend.