Nathan Redmond conceded Southampton's performance was "embarrassing" as they were annihilated 9-0 by Leicester City at St Mary's
The Saints went a goal down after Ben Chilwell's early strike and the floodgates opened when Ryan Bertrand was sent off after just 13 minutes.
Ayoze Perez and Jamie Vardy helped themselves to a hat-trick each while James Maddison and Youri Tielemans also got on the scoresheet.
Leicester equalled the biggest-ever Premier League win after running riot in a rain-soaked match on the South Coast and Redmond was under no illusions about how bad the Saints were.
"It was an embarrassing performance, the stuff of nightmare and especially playing at home.
"It just wasn't good enough and one of the poorest performances since I've been at the club and we’ll have to debrief that whole game from start to finish tomorrow.
"There were a host of things that went wrong - the red card decision and then the quick goal at the same time. We conceded goals far too quickly in the first half.
"We need to do much, much better. I think we had a few players out of position after the sending off and we tried to deal with it as best we could.
"There are the things we need to look at tomorrow but it was an embarrassing performance."
The result, the biggest away victory in the 131-year history of the football league, means Southampton drop into the relegation zone before their rivals have even played.
