Saints came from two goals down at the break to win the game but what can we take from this performance ?
Saints dominated the game for most of the 90 minutes but found themselves a goal down with Celta Vigo's first real attack of the game, a wonder goal from distance into the top corner leaving Alex McCarthy no chance.
Saints really should have been a goal up before this after a perfect cross from Ryan Bertrand had left Sam McQueen with what looked like a simple clear header from close range which he somehow put over.
The goal for the visitors seemed a minor set back with firstly Manolo Gabbiadini having a long distance shot saved and then Shane Long seeing a curling shot hit the bar, but just before the break the visitors doubled their lead, from a corner Shane Long gave the ball away and Aspas ran at Saints defence and fired home at the near post with a shot that really should have been saved by the keeper.
Saints made four changes at the break, the visitors six and ten minutes after the restart, a sublime cross from Matt Target on at right back saw him use his right foot to find Charlie Austin to reduce the arrears with a header.
Four minutes later and Saints were level, Stuart Armstrong who had looked good surging forward from the midfield took the ball laid it wide right for Matt Targett who played a nice little through ball for Armstrong to run onto and sweep the ball past the keeper.
The last half an hour saw a raft of changes and the pace slacken, Saints remained in control but although they had a few chances didn't look like getting the winner till the final minute when James Ward Prowse ran forward and unleashed a shot from 30 yards which beat the keeper but hit the post, it fell to Mohamed Elyounoussi who marked his home debut with a goal sidefooting into the empty net from 10 yards out.
A deserved win for Saints but what did we learn ?
In fairness it was hard to gauge as the game was full of changes on both sides and not at full temo for large periods, Stuart Armstrong looked strong, but then again so did every other Saints player, we seemed comfortable against the opposition and not stretched, no one was truly tested.
One thing is that Matt Targett should not be sold, he was comfortable at right back and showed he could use the ball with both feet, he can offer us options on both sides and could be a good replacement on either side of the pitch.
But it was a good workout and Mark Hughes will be nearer knowing who is going to play a significant part, who is going to be a bit player and who is really surplus to requirements.
At the back keeping Targett will keep us well covered in all areas, in midfield we have options in all areas, when you look at the fact that Nathan Redmond Josh Sims and Mario Lemina weren't even on the bench it shows that we are strong in that area.
That being the case he will perhaps feel that we are still a striker short and that could be the final piece in the jigsaw before the season starts, having said that Elyounoussi can supposedly also play as a striker so that may be an option going forward.
All in all Saints are going in the right direction though and you feel that the discipline needed is now in the squad, it is better than this time last year, we have plugged the gaps at the back, this was still an experimental game for Mark Hughes, perhaps Saturday's game will be less so with tougher opposition and a few questions answered.