Rochdale boss Keith Hill saluted a "special" day after his side sank Southampton 2-0.
Saints began the season as hot favourites for the title while Rochdale are widely tipped to return to League Two, but goals from Chris O'Grady and Gary Jones secured a memorable victory for the visitors.
"It is incredible to win at places like this," said Hill. "These are special days for a club like Rochdale.
"There can't have been anybody in the football world who thought we would win at Southampton. But we came here expecting to win and we did. It is a great result and a great performance."