Southampton sold around £100m worth of players - including Adam Lallana, Rickie Lambert and Dejan Lovren to Liverpool, Luke Shaw to Manchester United and Calum Chambers to Arsenal - during the close season.
But their new-look XI gave Liverpool a scare on the opening weekend of the Premier League season, before going down 2-1, and Irvine saw enough at Anfield to know his side will have to be on their mettle to get a result at St Mary's.
"Having been at Anfield last Sunday and watched how well they played and watched how many chances they were able to create at a really difficult place I think they can more than survive," he said.
"I think they could have a very good season. They have spent the money very wisely and replaced very good players with very good players.
"I was very impressed with how they played at Anfield. Not many teams go to Anfield and make it go quiet but that certainly happened during periods of the game.
"They deserved something out of the game last week and I believe it will be a very tough place for teams to go this season."
Among their recent additions is former West Brom striker Shane Long, a player Irvine knows plenty about.
"He's a very good player for a start and is going to be an important player for them, sometimes former players come back to haunt you," he added.
"We have just got to make sure if Shane does play from the start that we are ready to cope with the threat."