You're right, southempton always bring their best performance more especially when they are playing with bigger teams. on the second thought southempton is in the bottom of the table just about going for relegation this season, with this I think the match is going to be a little bit tough for liverpool. As liverpool will also want to reserve those thier key players ahead of thier upcoming match against psg in the champions league, I think that is thier major concern for now. But regardless to that I still have this strong believe that liverpool will gain victory over southempton.
In this match Liverpool is very advantaged, especially since they are facing a low-ranking team in the standings which will pave the way for Salah et al to get 3 points in the 29th match. Southampton will be overwhelmed in this match because they are no longer enthusiastic about improving their ranking because they are already quite far behind from a safe position in the standings.
Arsenal also get an easy opponent in the 28th match because they will face Manchester United. However, Arteta's squad must play better because they will visit Old Trafford which allows them to focus well because they must win this match so that they can compete strongly with Liverpool.