In the absence of skipper Jack Stephens, Downes has taken over the duty of skipper as he takes the chance to send a bold message to the Saints side who currently sit second bottom of the table with zero wins and just 3 goals in 6 games.
Downes spoke to BBC Radio Solent after the club’s 3-1 loss to Bournemouth which he says is simply not good enough.
"That first half, it's not acceptable at this level or any level to be fair.
"We let the staff down and the fans that travelled. We lacked the fight and there was no commitment or belief.
"We let everyone down. Going 3-0 down in the Premier League, you are asking for a lot. We started well, started sharp.
"We were caught out with a quick free-kick and then we sunk and it's exactly the same as against Manchester United.
Downes says the team need to look in the mirror, work harder and fight for 3 points as they seek to climb out from the relegation zone.
"We have got to look at ourselves, there is nothing anyone else can do - it's on the 11 players out there, we have to line up quick.
"It was fight, commitment and heart. You can talk about tactics all you want but you have to fight and earn the right to play.
"Whether you are going to go long or try and play football, you have got to earn the right or you've got no chance in this league - and we didn't.
"The fans deserve to see that fight every week. It's a given at this level, there is no other option. That first half was nowhere near it."
Southampton face Arsenal this weekend in what will be another tough test for the side which will be captained once again by Downes.