The 2-1 result saw United bounced out of the Champions League.
"They never played at a tempo which was enough to cause this average Seville team a problem," said Souness on Irish channel TV3.
"They never did until Seville scored basically. They couldn't get out of that second, third gear.
"No imagination. (They) resorted to just lumping it to a big centre forward, looking for second bits off him.
"Fellaini's on the pitch - that tells you which way they want to go, thinking they'll get something at a set-piece.
"It ain't good enough."