The Saints were beaten 1-0 by Newcastle United, despite having a man advantage for much of the game.
They lost to the Magpies at St. James’ Park in their first game back in the Premier League after gaining promotion from the Championship.
He told Sky Sports: "For the first game back, I thought there were plenty of positives and we can kick on for the next game.
"I think it was more the build-up before the goal that we touched on. Not passing and moving quick enough - that led to it.
"It's nothing on Alex McCarthy, he's been brilliant - we saw last season as well. That's the way we play and we are enjoying it.
"We are going to be really attacking this year and we want to cause some upsets as well. We saw the three promoted teams come down last year.
"We know people will have written us off but we will keep working hard on the pitch. We definitely don't want to get relegated.
"We could have taken a result, Newcastle are animals - I have seen it for years being a fan, they defend the box so well and that's what you need.
"You need to punish teams and we didn't do that today but the lads are really confident in the dressing room and we'll take each game as it comes."