Last-place Reading plunged closer to relegation from the Premier League after losing 2-0 to Southampton on Saturday for a club-record eighth straight defeat.
Jay Rodriguez put Southampton ahead in the 35th minute, exchanging passes with strike partner Rickie Lambert before bundling a scruffy finish home as he challenged for the ball with Reading goalkeeper Adam Federici.
Rodriguez, who also struck a shot against the crossbar, then provided a deft pass for substitute Adam Lallana to score the second in the 72nd minute.
Southampton took a giant stride toward safety with the win, which lifted Mauricio Pochettino's team seven points clear of the relegation zone.
By contrast, Reading looks doomed in its first season back in the top flight. The team is seven points off safety with six games remaining.
"It's a situation we don't want to be in, but we're in it," said Reading manager Nigel Adkins, who had been looking for revenge against the club that fired him 78 days ago. "You can hide away or you can face up to the reality of it."
Reading will point to a glaring early miss by Adam Le Fondre, when he blazed over from close range when the score was 0-0, as a turning point.
There was also a moment of controversy when Southampton goalkeeper Artur Boruc appeared to carry the ball over his own line after collecting a header by Noel Hunt in the 76th minute. Video replays were unclear whether the whole ball had crossed the line - if a goal had been given, it could have sparked a late comeback from the hosts.
Southampton, though, fully deserved a third straight win to continue its resurgence under Pochettino.
"I think he's given us a belief," man-of-the-match Rodriguez said of his Argentine coach. "He's very passionate, he's very good in tactical situations and the team spirit is there. It's a great feeling to be on the winning side."