Lopetegui drew a lot of positives from the performance at St Mary's.
He explained, "We were really pleased with the win at Southampton, to make it eight points from a possible 12. We handled a very tough match and we handled big problems with injuries and this kind of situation.
"So, we have to keep with this mentality and to be ready for the next challenge that is going to be enormous (against Liverpool), and we have to be ready to use all our players.
"It’s important we get as ready as we can for the next challenge. We have to try and take advantage of the situation with the players we’re going to need. This is the moment to highlight the word ‘TEAM’ with capital letters, because we have a lot of players out and we’re going to need everyone (that's) available.
"This sort of situation happens though, so we have to be ready to face it in the best possible way. I often highlight the importance of our bench players, and the likes of Alphonse (Areola), (Jean-Clair) Todibo and Edson (Álvarez) showed they were ready to come on and perform (against Southampton).
"With (Aaron) Cresswell, he has been injured for two weeks, and came on to play in a key part of the match, and it’s the same with Vladi (Coufal) and (Crysencio) Summerville. We need this kind of mentality because all of the players are going to be main actors at different stages of the season."