The 25-year-old academy graduate has stuck with Saints through thick and thin, playing an integral role in their rise to the top flight after falling into administration and League One.
Lallana has grown to become one of the Premier League's most exciting attacking talents and one that Southampton manager Mauricio Pochettino, a former Argentina international, believes would not look out of place playing for Spain or Brazil.
Those sentiments are echoed by midfielder Cork, who was first taken aback by the Saints captain during a loan spell at St Mary's in 2008.
"He was running past people in training and I was saying 'it is crazy how good he is'," Cork, who made his move to Saints permanent in 2011, said.
"I think Adam has got unbelievable qualities and is such a good player. I see it everyday in training.
"Some of the stuff I see you have to take a second look at and take a step back and say 'what just happened?' because he is so good.
"The qualities he has is just amazing. He can create something out of nothing all the time.
"It is just good knowing that you can sit back and someone like that, Jay or Rickie is going to do something magical and win you a game.
"There is no reason why Adam couldn't fit into any of the top sides in Europe or world football because he is that good."
Such talent makes Cork believes England would be foolish not to use him at the World Cup.
Asked if Lallana should be an automatic choice, Cork said: "Yeah, I think so. I think he offers something different to what other English players have.
"We have a lot of wingers that are quite direct and quite pacy and I think Adam is a bit more clever. He can see the ball, manipulate his feet quicker than some other players.
"I think just having that cleverness in the England team is just something different we could maybe work with."
Lallana believes the midfielder's half-time introduction was key to last weekend's 3-0 win at Fulham - a match which came just after the January transfer window in which Swansea saw a last-ditch offer rebuffed.
Cork was happy to see that bid rejected, but admits there were times earlier in the campaign when he did consider his future.
"I think if you had asked me earlier in the season, I might have said something different," he said.
"Obviously Victor Wanyama came in and I wasn't playing as many games as I would like to have been playing at the start of the season.
"That changed in November, December time, playing a lot more games and I think it showed that I still had a part to play in the squad and in the team.
"Hopefully if I can keep the form going, I can still have a big part to play in the team. I will see what happens in the future and towards the end of the season."
Wanyama was one of three big-money summer additions made by Saints, along with Dejan Lovren and Dani Osvaldo.
The latter, though, has already left the south coast after an ill-fated five month stay.
Arriving for a club-record fee, Osvaldo rarely lived up to his billing and, after an altercation with team-mate Jose Fonte, was loaned to Juventus with the view to a permanent move.
"We've got such a tight group of players and everyone gets along really well," Cork said.
"I mean Dani was a really good lad as well. I am not really too sure what happened with the whole situation - I think that's between some other lads in the club.
"We've got such a good group here and I don't think anyone wanted to upset the bond we had."
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- Mauricio Pochettino