The duo meet in Group I having each won both of their games to date in a group which also features Salzburg and Nice.
It means their clash on Thursday could have a significant bearing on who tops the standings and a win for either side would all but guarantee their place in the knockout stages.
Nastasic admits the trip to southern Russia will be tough for his side and acknowledges just how important claiming all three points could prove to be for Die Konigsblauen’s season.
“We are facing a top team who have a lot of quality players,” he told the club’s official website. “I have watched both of their matches so far. They already have six points from two games.
“We want to get points from the match against Krasnodar in order to qualify for the knockout stages as quickly as possible. Getting three points would be a huge step forward for us and then we can concentrate fully on our upcoming Bundesliga fixtures.”
Southampton have announced plans for a two-week tour of China as part of their pre-season preparations for the 2018-19 season.