Everton manager Marco Silva has called on Richarlison to learn fast from his "naive" sending-off against Bournemouth on Saturday.
The Brazilian forward, who joined Everton for a club-record £40m earlier this summer, was dismissed four minutes before half-time of his side's 2-2 draw at the Vitality Stadium.
Richarlison clashed heads with Bournemouth right-back Adam Smith, with referee Lee Probert wasting no time in brandishing the 21-year-old a straight red card after he appeared to lean his forehead into his opponent's.
However, Silva had little sympathy with his player.
"It is naive, it is something Richarlison can't do," Silva said after the game.
"It is something for the boy to learn fast, but it is something we can see many, many times in a football match.
"Both players to put their heads against one another and with minimum contact or movement as well. But it is something he cannot do."
Despite letting a two-goal lead slip, though, Silva was impressed with his team's display on the south coast as the visitors maintained their unbeaten start to the campaign.
"Amazing, our 25 minutes in the second half we did amazing," said the Portuguese.
"I asked them to keep our shape, good organisation again, but never give up and always believe we can score.
"And we did, and our first goal is a fantastic example after we have a fantastic chance to score the second with a free kick. And after we score the second as well.
"And until 70-75 minutes it looks like the game is in our hands, but in football at this level, you have to keep your balance every time and you cannot give chances to our opponent when playing away and winning 2-0 to put counterattacks against us."
Meanwhile, Silva also faces an anxious wait to discover the severity of the injury suffered by Michael Keane at the Vitality.
England defender Keane was given lengthy treatment on the field in the closing stages of the game following a nasty collision with team-mate Idrissa Gueye.
The 25-year-old, who scored Everton's second goal, left the pitch on a stretcher and was taken to hospital for assessment.
Silva said Keane's condition was his biggest concern after his team surrendered a two-goal lead.
"First and most important, believe me," he said about Keane's injury.
"He went to the hospital, I don't have more updates about the situation. When he went to the hospital, in that moment it looks a little bit better, in better condition as well.
"I hope everything is OK now, but we have to wait."