A clash with Baggies boss Roy Hodgson has not helped Odemwingie, 30, who rattled in 15 last term after joining from Lokomotiv Moscow.
But Morrison, who fired a superb opener, said: "Pete will be the first to admit he hasn't been his old self this season.
"On his day he's fantastic, a match-winner. He's a confidence player and when he's got that he's unstoppable. It can take a goal like that to spark you off."