Mexico were made to pay for errors in the 3-1 defeat to Argentina which has sent them out of the World Cup, coach Javier Aguirre said.
Mexico went behind to a goal by Carlos Tevez which replays on the giant screens at Soccer City stadium showed to be offside, but the Mexicans only had themselves to blame for the second after Gonzalo Higuain punished a mistake by defender Ricardo Osario, DPA reported.
"After the referee gave that goal which was offside we lost our concentration. The second goal was our own fault and we found ourselves 2-0 behind and that is too much to catch up," Aguirre said.
Mexican players protested after referee assistant Stefano Ayroldi failed to raise his flag for the offside for the opening goal.
Referee Roberto Rosetti consulted with the assistant as Argentina players, fearing the goal would be disallowed, also crowded round the officials.
Even after the final whistle, some Mexican players approached the linesman to discuss the goal.
"The first goal sort of took away our will and orientation. We lacked the power to overcome that, and the second goal wasn't necessarily fatal but it was hard to come back after that," Aguirre said.
"I told the boys, 'Heads up, stand proud and tall, be calm and cool in what you say.' Football is just one thing, everyone is human and makes mistakes, referees take split second decisions and can spoil everything."
Mexico bowed out after defeating France 2-0, drawing 1-1 with hosts South Africa and losing 1-0 to Uruguay.
Looking back at the games, Aguirre said the team ultimately lacked consistency.
"We didn't have a continuous quality in our football and we are paying dearly," he said.
"I am not happy and I am the one who was responsible for that. I did what I was able to do, there was something missing. Nevertheless, we can face the future with optimism.
"It is a great generation of young Mexican players. I believe in four years from now they will be at the top."