Wolverhampton Wanderers manager Nuno Espirito Santo has been fined £25,000 ($34,000, 28,000 euros) and warned to his future conduct following public criticism of referee Lee Mason.

Nuno said Mason was not good enough to officiate in the Premier League following Wolves' 2-1 loss to Burnley on December 21.

England's Football Association said Wednesday that Nuno had accepted a charge of improper conduct following a personal hearing.

"The (Wolves) head coach admitted that comments he made during a post-match interview constitute improper conduct as they were personally offensive to the match official and bring the game into disrepute contrary to FA Rule E3.1," said a statement from the ruling body.

Nuno, following the match at Turf Moor, said of Mason: "The referee does not have the quality to whistle a game in the Premier League.

"It is not about the crucial mistakes or decisions, it is about the way he handles the game.

"We are talking about the best competition and clearly he doesn't have the quality to whistle the game."

The Portuguese boss added: "I just don't want to see him more -- that's what I told him. I hope he doesn't whistle a game of ours again because all the games we have with Lee Mason are always the same. He cannot control the players."

Two days later Nuno apologised for the timing of his comments but not for the thinking behind them.

"They were not in the best moment to come across because it could be a bad interpretation," he said. "For that I will apologise on my timing, but I won't apologise for my words and thoughts."

The FA charged Nuno on New Year's Eve and a fine was handed down at a hearing in front of an independent regulatory commission.