Jason Puncheon's late winner helped Southampton beat Real Sociedad 4-3 in yesterday's friendly.
Adam Lallana, Morgan Schneiderlin and Jos Hooiveld scored Saints' other goals.
"I think we've done well, but there are certain things we need to improve in from this game," manager Mauricio Pochettino told Saints Player at full time.
"I have a bit of a bittersweet feeling but, from analysing the goals we conceded, I think there are things we can correct.
"The team did a lot of good things, but overall we still have a week to make adjustments to how we want to play and set out in games.
"I think Real Sociedad scored through our mistakes, so those are things we need to look at.
"We're hoping that what happened to Luke Shaw isn't too serious," continued the gaffer.
"We have a bitter feeling because we've been playing well without getting injuries.
"Hopefully it's nothing too serious and that we can count on him for the start of the season.
"We need to know what the doctors say, but he has a bit of a problem with his knee ligaments. Hopefully he will be okay."
