The forward came on for the last quarter-hour of Sunday’s narrow defeat at Anfield having completed his move from Hull City three days earlier.
And, after running Liverpool so close in the opening game of the campaign, Long is already looking forward to this weekend’s visit of his old side West Bromwich Albion.
“It felt good to get on the pitch, and I thought the lads were brilliant in the second half,” he told newstalk after his debut.
“We caused Liverpool all sorts of problems, and if anyone looks like they were going to win it, it was us.
“I think we got clapped off the pitch at the end – that’s how good a performance we put in. It’s frustrating not to get anything out of the game, but there are a lot of positives to take.
“We’ll work hard this week to build towards West Brom at home and hopefully we’ll get the three points then.
“They (Saints) had been planning for this all pre-season – you could see from how well they were organised – so it would’ve been hard for me to come in after two days and slot straight into the team,” he continued.
“Hopefully, with a week’s training under my belt, I can force my way into the manager’s thoughts for the weekend.”
Long says his first week as a Saints player has been a positive one, and that the fee paid by the club to take him from Hull City has made him feel valued rather than generate pressure.
“I don’t know whether there were any offers that were rejected before, but when you see them bid that much to get me, I know personally that they wanted to get me in so that gave me a bit of confidence,” he reasoned.
“I think they realised that I was one of the starters every week for Hull, so to get me out of there was going to take an offer that makes you sit up and take notice.
“After talking with the manager and seeing the club and its facilities, it was right for me.
“When you walk into the club, you see how professional it is every day – everyone’s on each other’s cases and pushing each other. That’s why we were very fit and ready to go [on Sunday].”