The hosts ran out 4-3 winners over Real Sociedad, but manager Pochettino was left fretting over the fitness of left-back Luke Shaw, who limped off with a knee injury just before the break.
"I think we've done well, but there are certain things we need to improve in from this game," he 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."
Pochettino also confirmed that he is hopeful that Nathaniel Clyne will be fit to feature in Saints' season-opener at West Bromwich Albion next weekend.
The right-back has missed the last three games with an injury picked up while on tour with the First Team, but is nearing a return.
"We want him training with us from the start of next week," said Mauricio.
"If that happens, he will have his chance of starting against West Bromwich Albion."