The result leaves Reading bottom of the Premier League, seven points from survival, with 17th-placed Wigan Athletic having two games in hand. Goals from Jay Rodriguez and Adam Lallana did the damage as Reading failed to take advantage of their spells on top.
The hosts appeared to be well-motivated for the clash and got off to a very positive start, and created their first chance very early through Danny Guthrie, the former Newcastle midfielder sending in an excellent delivery from a free-kick to find Sean Morrison at the back post, but his header was off-target. With both sides probing, the first real clear-cut chance also came to the home side, as a goalmouth scramble eventually saw the ball fall to Adam Le Fondre, unmarked, six yards from goal. Uncharacteristically, the striker blazed his effort over the bar for what will go down as a sitter.
Reading were soon aggrieved for different reasons as claims by Hal Robson-Kanu for a penalty were waved away after he went down under a challenge from Jos Hooiveld. It was a fairly agricultural tackle from the defender, although replays show he did get most of the ball before coming into contact with the Welshman.
Shortly afterwards, they were soon ruing the missed opportunities as they found themselves behind, against the run of play. Rickie Lambert had been given a free-roaming role behind Jay Rodriguez in attack, and the two combined as the Saints put together a fine passing move which saw Lambert chip a ball over the top for the former Burnley man, who managed to prod the ball under the advancing Adam Federici and into the net. Reading appealed for a foul, but there was to be little mercy coming from the officials.
The goal appeared to shake the hosts and Southampton were on top for the remainder of the half, twice going close again. Rodriguez hit the bar with a fierce effort shortly afterwards after good work from Gaston Ramirez, before Lambert and Rodriguez combined once again to set the latter through on goal. His shot was saved, and the rebound fell to Ramirez for a good chance, but the Uruguayan mishit his shot just wide.
After half-time, Reading tried to force the issue, and although the home side enjoyed more possession, Southampton were cutting them open on the counter-attack through some pinpoint passes from Rickie Lambert. Steven Davis and Jay Rodriguez were both released by the big striker for chances on goal, but both times Federici saved to keep his side in the game.
As the half wore on, however, Reading began to fade, and Southampton began playing more of the possession football that has typified Mauricio Pocchettino's tenure. They soon had their killer second goal, through yet another fine passing move, Rodriguez turning creator to find Lallana's run into the box, and the winger slid home to all but put Reading out of action.
Reading almost pulled one goal back immediately, however - Adam Le Fondre getting his head onto a deep cross to trouble Artur Boruc, who almost carried the ball over the line with his catch. No goal was given, much to the fury of the home fans, although replays showed that the decision appeared to be correct, by a tiny margin.
In the end, Reading could not force any additional pressure having spurned their earlier chances, and it appears Nigel Adkins will be rebuilding his side in the Championship next season. It's not over yet, but Reading simply don't look like they have the quality to pull out an escape act of this magnitude.