Wayne Rooney's form has concerned Sir Alex Ferguson so much he has taken time out from his holiday to call the England forward.
Ferguson claims the "debilitating" atmosphere in the England camp is affecting Rooney, but also added that a long campaign has taken its toll on the 24-year-old, who has looked a shadow of the player that scored 34 goals for United last season.
"I had that feeling," Ferguson said. "I spoke to Wayne last week and I just said: 'Relax and enjoy it.' I just sensed there was a tension in and around the camp from what I was hearing. I didn't watch the Algeria game but I just get a feeling that the expectation is affecting the England team.
"Sometimes the expectation can be debilitating in terms of getting the players to perform to the levels required to get through their group."
The pressure appeared to get to Rooney after the 0-0 draw with Algeria, when he angrily criticised England fans as he walked off the pitch.
Rooney is far from being the only underperforming player at the World Cup, but that does not surprise Ferguson.
"It's been a disappointing World Cup but I had a feeling it would be," he added on Sirius radio in New York. "I have been disappointed with the quality levels, I have to say. I haven't been impressed at all.
"The season we have in Europe, particularly in England, is tough. Then the players all met up [with their international squads] three or four days after the season finished and they have been together for most of that time, after a long, hard season.
"It's a real task to ask players to perform at the best level they can after a season in England.
"Germany take that month-long break in January and they always seem to do better in World Cups than anyone ever expects. Even though they are not as strong as German teams of the past, they still manage to do something in World Cups."
Rooney is not the only United player to be struggling in South Africa, as defender Patrice Evra has endured a miserable time captaining the fractured France squad, a team that could soon be inherited by Ferguson's former player Laurent Blanc who is set to take over as coach after the tournament.
"I didn't expect them to do well, but I expected better than what we have seen," Ferguson said. "There seems to be a lot of disharmony in the camp.
"I think it was bad preparation for the players to know that (the manager) Raymond Domenech was leaving and that Laurent Blanc was going to be coming in after the World Cup. They should have brought Blanc along as an over-seer or assistant just to get a look, and maybe he would have had a calming influence and brought a bit of harmony into the squad."
However, Ferguson was happy with the performance of new signing Javier Hernandez, who was in the Mexico side that beat France to 2-0, scoring the first goal, to leave Les Bleus' early exit.
"He did very well," Ferguson said. "He showed good movement, quick and sees space very well. I was very pleased with his performance."