READING FC fell to a heavy defeat as Ruben Selles made his first appearance as the Royals boss in front of the home crowd.
Selles’ former team made a fast start and netted twice in the opening 10 minutes before new arrivals Sam Smith and Harvey Knibbs combined to reduce the deficit.
Saints continued their domination in the second-half and scored twice more through Adam Armstrong and Joe Aribo to claim a comfortable win before Royals trialist Olamide Shadipo netted late on.
The Royals turned out for their first encounter in front of their home supporters under new boss Ruben Selles.
The Spaniard was up against his former club Southampton, who were relegated from the Premier League and are preparing for life in the Championship under newly appointed Russell Martin.
There were plenty of new faces on show for Reading in a starting line-up that saw places for both Harvey Knibbs and Sam Smith, as well as trialist Tivonge Rushesha.
The Saints came out of the traps fast and scored with just three minutes on the board when Jan Bednarek met a James Ward-Prowse corner unchallenged and nodded into the far corner.
Southampton built on their quick start, but Sekou Mara was unable to provide the finishing touch.
The visitors doubled their advantage with a neat move down the right which saw Tino Livramento and Nathan Tella combined before Ward-Prowse poked in from close range.
Reading were struggling and looked well off the pace in the opening 20 minutes having only had limited time and a reduced squad to work with.
However, they did to get on the scoresheet as new signings from Cambridge United, Knibbs and Smith combined.
Knibbs forced Bednarek into a mistake at the back and stole possession before he was joined in attack by Smith who unselfishly fed the ball back to his teammate and Knibbs stroked the ball past Gavin Bazunu to notch his first goal in Reading colours.
Goalkeeper Dean Bouzanis was called into action a few times to prevent Southampton from furthering their lead as he kept out shots from Adam Asmstrong and Tella.
Femi Azeez showcased his athletic ability when he broke away through the middle, but he had no outstanding options and was forced to shoot from distance and ultimately missed the target.
Selles made two changes going into the second-half as Jokill Andersson replaced Bouzanis in goal, while trialist Olamide Shodipo came on for Smith.
Southampton added their third of the afternoon just five minutes after the restart when Armstrong picked out the bottom corner to beat Andresson.
Azeez had the chance to reduce the deficit when he broke behind the Saints backline and with just the goalkeeper to beat, the Saints stopper made an excellent save with an outstretched leg to frustrated the Royals.
With 30 minutes left, academy player Caylan Vickers was brought on to replace Knibbs.
Saints threatened to make it 4-1, but Andersson stood in the way to make a smart stop and just moments later came out with an even more impressive save to prevent a shot from point blanc range.
With 20 minutes left on the clock, Selles made eight changes.
Southampton’s supremacy continued and they scored a fourth when Sam Amo-Ameyaw breezed past the Royals defence and teed up Aribo to apply the finish.
Reading managed to claw a goal back late on when Olamide Shodipo squeezed the ball beyond the keeper.
Reading host Swansea City next weekend in their final pre-season match before the start of competitive action the following week at home to Peterborough United.
Reading: Bouzanis, Abrefa, Holmes (c), McIntyre, Guinness-Walker, Senga, Rushesha, Azeez, Knibbs, Ehibhatiomhan, Smith
Subs: Andresson, Axande, Carson, Shodipo, Borgnis Djorkaeff, Abdel Salam, Craig, Dorsett, Vickers, Bindon, Camara, Abbey
Southampton: Bazunu, Livramento, Bednarek, Stephens, Walker-Peters, Smallbone, Ward-Prowse, Alcaraz, Tella, Mara, Armstrong
Subs: Manning, Caleta-Carr, Aribo, Adams, Bree, Djendpo, Edozie, Charles, Amo-Ameyaw, Lavia
Goals: Bednarek 3’, Ward Prowse 9’,, Armstrong 50’, Aribo 76’, Shadipo 89’
