Last season Roberto Mancini's side incredibly overcame an eight-point gap on Manchester United in the final three weeks to secure a first title since 1968.
However, City look unlikely to repeat the feat this term as Manchester United already post a nine-point lead at the top.
Joe Hart has admitted defeat at St Mary's would all but end their hopes of retaining the title - something Lallana has echoed in the build-up.
''Yeah I agree,'' the Saints skipper said. ''I think if we beat them and United win, it would be a 12-point gap.
''I am not really looking at that end of the table as I'm concentrating on the other end at the minute.
''But if that is what Joe Hart says, he is an experienced character and player. As an England international, he knows his stuff.''