Wednesday recovered from a first half Southampton masterclass only to be beaten at the last in this Championship curtain-raiser at Hillsborough.
After Adam Armstrong gave the South Coasters an early lead there seemed only one winner as Saints stroked the ball around with ease.
But for all their possession, a potentially decisive second goal never came before the break and the Owls regrouped for the second half with the bit between their teeth.
Lee Gregory fired an equaliser that gave Wednesday and the S6 crowd a huge boost – until they were undone with three minutes to go by Che Adams, who came off the bench to seal victory.
Follow a promising start, during which a goalmouth scramble almost ended in an Owls opener, Saints struck eight minutes in.
Nathan Tella took possession just outside the box on the angle and looked up to execute a curling drive that deflected off Armstrong and into the top corner.
That put down a marker for the recently relegated visitors, who promptly began to show their Premier League class.
Carlos Alcaraz advanced to unleased a fierce shot from distance that whistled wide and Southampton went on to boss a one-sided first half, keeping the ball at will for extended periods.
Wednesday struggled to get out of their own half but 10 minutes before the break, Tyreeq Bakinson offered a glimmer of hope with a looped long ranger that had Gavin Bazunu springing across his goal.
And Gregory went one better eight minutes into a second period that the Owls began well.
Will Vaulks swung over a corner headed back across goal by Dominic Iorfa and Gregory swept a sweet volley home.
That gave Southampton a jolt and both teams looked different sides.
Buoyed by the goal, Wednesday started to show a little swagger. Anthony Musaba came off the bench and immediately went on a lung-busting run into the area only to be halted by a well-timed Jan Bednarek challenge.
If there was to be a winner this time, the Owls were favourites - but substitute Adams had the final word.
The striker applied the finishing touch from close range to a swift Saints counter and Wednesday were left down but most certainly not out on their second tier return.
Wednesday: Dawson, Paterson, Iorfa, Ihiekwe, Famewo, Delgado (Fletcher 77), Vaulks (Palmer 77), Bakinson, Bannan, Windass (James 86), Gregory (Musaba 68)