Wrexham suffered a double gut punch as Southampton struck twice late on for a dramatic 2-1 victory at St Mary's.
Josh Windass put Wrexham ahead on their return to the second tier of English football after a 43-year absence, converting a 22nd-minute penalty when fellow summer recruit Kieffer Moore was fouled.
Southampton -- two divisions higher than Wrexham last season -- pushed furiously throughout for reward, but they were fast running out of time when substitute Ryan Manning dispatched a superb 90th-minute free kick.
Saints were not done, though, as Manning burst down the left in the sixth minute of added time to deliver a cross that Jack Stephens lashed in off the crossbar at the back post to floor the club owned by Hollywood pair Ryan Reynolds and Rob McElhenney.