Southampton are bottom of the table on 24 points from 36 games and will be heading back to the second-tier Championship 11 years after they were promoted to the Premier League in 2012.
The south-coast club earned a reputation as a leading developer of talent in a spell during which they finished in the top eight for four straight seasons, but they have gone from the brink of European football to being involved in relegation battles in recent years.
Southampton have finished 15th or lower in four of the last five campaigns, with their steady decline culminating in a dismal run this season, in which they have earned only six league wins, while racking up a club-record 24 defeats.
They are also under their third manager of the season in Ruben Selles, following the sackings of Nathan Jones and Ralph Hasenhuettl.
"It's disappointing. It is a moment that has been coming. We knew we had put ourselves in a difficult position," Ward-Prowse said.
"When these things happen you go away individually and as a club and ask if you have done enough? I don't think we have. We talk about leaving things out there and ultimately that is why we are where we are now.
"I believe we should be performing at a better level than we have done and we have not done that on a consistent basis. The standards have slipped away and that is why we are where we are now."
Ward-Prowse, who came through Southampton's academy, has made 341 Premier League appearances for the club, but could leave in the close season transfer window.
Asked about his future at Southampton, he said: "I'm not thinking too far ahead. We've just been relegated from the Premier League. I'm not looking beyond tomorrow. It's about sticking together and dealing with it in the right way.
"Over the last 10 years we have had that kind of consistency and that has wavered. It will be testing for everybody but these are the times that make you as a player and as a club, we have done it before and we will do it again.
"I have been here right through from eight years old, for all the ups and downs. I'm sure with the good people at the club it will be back in the Premier League in no time."
Southampton travel to Brighton & Hove Albion before hosting Liverpool in their final game of the season.
