Southampton have now won all three games that interim boss Tonda Eckert has managed
Southampton thrashed Charlton in the Championship, scoring five times in the first half in a game where all the goals came in the first 45 minutes.
Ryan Manning headed home the opener before Adam Armstrong and Caspar Jander made it 3-0 inside 20 minutes.
Finn Azaz then scored twice before the break, although Charlton managed to get one back just before half-time as Lloyd Jones headed home from a corner.
Tonda Eckert has now won all three games in charge as interim Southampton boss to lift them well clear of the relegation places and in sight of the play-off spots.
They are two points behind Charlton in mid-table, the Addicks slipping to a second successive loss as boss Nathan Jones suffered a chastening defeat at the hands of his former club.
Southampton opened the scoring in the 14th minute as Manning crashed into the box and nodded the ball into the top corner of the net after a cross from the right.
Two minutes later, Armstrong doubled the lead, finding himself in space and seeing a shot blocked before following up with a lashed effort, high into the net from an angle on the left.
Saints' third goal was a fine footballing move as Gavin Bazunu started with the ball almost on his own goal line before then starting a sequence that saw Eckert's side work the ball beautifully up the pitch.
As they moved towards the halfway line, Armstrong swivelled in possession before playing Jander clean through on goal and he - after a fair dash - provided a composed, low finish with his right foot.
Azaz then made it four after Armstrong found his piercing run into the box and the summer signing took the ball around Charlton keeper Thomas Kaminski before slotting it home.
The Republic of Ireland international then scored a fifth for his side two minutes before half-time. Tom Fellows made a run down the right and then sent a powerful cross across the face of goal, with Azaz on hand to poke it home at the back post.
Just before the break, Charlton managed to get a goal back as Jones rose highest to head the ball home from a Sonny Carey corner.
Saints appeared to take their foot off the pedal in the second half and almost played themselves into trouble at times but managed to escape without conceding again.
This was just Charlton's second home loss of the season, their only other league defeat at The Valley coming against Leicester in August.
'We did not do the things we normally do' - reaction
Jones: 'We showed them too much respect.'
Charlton manager Nathan Jones told BBC Radio London:
"Give credit to them, for 20 minutes they were as good a side as we have seen at this level [but] could we have been a bit more aggressive? We did not do the things we normally do and that is basically what has cost us.
"We do not defend the box well enough for the first goal, we allow certain things to happen for the second which kind of kills it, and then they go up and level and make it three and four very quickly.
"We showed a lot of character in the second half, we tweaked it defensively – we were probably a little more reserved than we normally are. Credit to Southampton they were much better than us but that is a learning curve for us.
"We are stretched. We have four fit defenders and one could not play today because it is against his club; wingers in wing-back positions, so it's tough.
"We did not quite get things right, we gave them too much respect.
"We were deep and weren't aggressive in winning that first ball that we normally do and then they had runners and quality and real technique to go and hurt us and we looked open, which is not something we normally do."
Eckert: 'If you get that one pass right; there’s a whole pitch to open up'
Interim Southampton head coach Tonda Eckert told BBC Radio Solent:
"We knew that they would be coming for us and that obviously gives you space further up the pitch and I think we used them quite well.
"We are very very happy to have Adam [Armstrong] as a character, as a player on the team – with the quality he brings, it's very nice to have him up there and he recognises moments like nobody else.
"Those teams are tough to play against, when you know they are coming for you. You will have a little bit more space between the lines and if you get that one pass right, there is a whole pitch to open up.
"We worked on this [over] the last [few] days and it came off.
"After the break, you just have a couple more days to prepare and we did that well."
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