LONDON • Ronald Koeman accused Sadio Mane and Victor Wanyama of "lacking focus" and letting the club down after Southampton lost 0-1 to Norwich on Saturday.
The Saints manager was furious that he had to rearrange his game plan two hours before kick-off at Carrow Road because Mane turned up late for a team meeting.
Wanyama caused further disruption by getting sent off when the score was 0-0.
Four minutes later Alex Tettey scored the winning goal for Norwich.
Koeman said he will speak to the Southampton board about how to punish Mane and Wanyama.
Koeman was particularly angry with Mane because he had warned the player about his attitude on Thursday, having noticed that the Senegalese forward appeared distracted in training.
Koeman claimed he did not know whether the transfer speculation linking Mane with a January move to Manchester United was to blame.
"My message to Sadio was that I think he wasn't really focused and concentrated," said the Dutchman.
"He was not doing things in the training session how I like football players to do them."
That context, and the fact that Southampton chairman Ralph Krueger gave the whole squad a speech on New Year's Day in which he emphasised the values they need to uphold, made Koeman all the more vexed with the player's late arrival for the matchday meeting.
"Sadio was in (the team) but we have rules and he was doing a big mistake because he came late and that's impossible," said Koeman.
"I don't understand players who come late, and everybody knows we have a sanction."
Mane knows it especially well, as he was dropped last February for a similar offence before a home match against Liverpool.
"You have to make changes in the teams, in the set pieces, in everything," added Koeman.
He was also aggrieved by the behaviour of Wanyama, another player linked with a transfer away, with Tottenham Hotspur and Arsenal among the Kenyan's admirers.
Wanyama was booked in the first half here for a crunching late tackle on Nathan Redmond and was sent off in the 72nd minute for another ugly tackle, this time on Vadis Odjidja-Ofoe.
"A player with his experience needs to know if you have a yellow already you can't do that," said Koeman. "You have a responsibility to the fans, the team-mates, the board, the technical staff - losing is part of the job but sometimes we do it to ourselves.
"This is very painful. I will talk to the board and the players, I'm angry about what happened."
In addition to indiscipline, Southampton were undone here by wayward finishing.
Even without Mane and their injured top scorer, Graziano Pelle, they created enough chances to take the lead, with Shane Long missing several opportunities before Norwich scored.