It's another vital win for Nigel Adkins' men as they bounce back from defeat at Liverpool with victory against a Royals side which has now lost four games in a row.
Jason Puncheon’s fine second-half strike proved the difference as the visitors rarely created any meaningful openings, despite while Hal Robson-Kanu header against the post on the stroke of halftime.
The win pushes Saints out of the relegation zone and continues their fine run of form, while Reading is consigned to a fourth defeat in a row.
Nigel Adkins made two changes from the defeat at Liverpool, with Kelvin Davis starting in goal ahead of Paulo Gazzaniga, while Jay Rodriguez got the nod in place of Gaston Ramirez, who made the Saints bench.
Brian McDermott named an unchanged Royals side from the dramatic 4-3 defeat at home to Manchester United, with Adam Le Fondre starting up front alongside Jason Roberts, while Pavel Pogrebnyak missed out through injury.
It was a bright start for the home side as Jose Fonte headed down Luke Shaw’s cross towards Jay Rodriguez, who blasted low into the side netting from a tight angle.
Rickie Lambert drove a 25-yard volley wide before Southampton had another glorious chance to go ahead as Puncheon set Nathaniel Clyne loose on the right, but his drilled cross hit Morgan Schneiderlin in the chest and rolled wide.
The visiting side started to enjoy more possession, but was’t creating anything meaningful as the Saints defense stood firm. Lambert then had another attempt, curling an effort across goal which Federici did well to palm away.
Jay Tabb produced a superb counterattacking run to burst forward and drive an effort towards goal, which Davis comfortably parried away.
The home side then had a goal disallowed as Puncheon headed in at the far post from a corner, but the referee had spotted an infringement in the area and it didn’t count.
Southampton started brightly after the break and Puncheon forced another fine save from Federici as he tried a low curling effort from the edge of the box, before Rodriguez volleyed just wide from 25 yards.
Finally the home side took the lead on the hour as Lambert released Clyne who played a superb pass for Puncheon to gather and roll the ball across goal into the far corner.
Jobi McAnuff immediately had a chance to level after Clyne’s botched clearance, but blasted the ball well over the bar.
Puncheon drove another effort wide, this time from distance, before moments later substitute Guly Do Prado fired an excellent curling strike just over the bar.
Davis was then forced to punch away a Shorey free kick before Do Prado wasted a glorious opportunity, firing straight at Federici from 10 yards, but the home side held on to register another win and leap out of the relegation zone.