Costa Rica coach Jorge Luis Pinto is worried Arjen Robben will try to give Netherlands an advantage by diving in Saturday night's World Cup quarter-final in Salvador.
Robben was accused of diving to win a penalty in Netherlands' second-round match against Mexico.
The winger denied the accusation but did admit to exaggerating a fall earlier in the match. And that has Pinto concerned ahead of Saturday night's last-eight meeting.
"This is one of the most important questions I have been asked in this World Cup," Pinto said. "Diving. This is something that makes us worry a lot. We're really worried about that.
"I would like to ask FIFA and the referees to watch Robben closely. We're really worried about his diving.
"He has admitted to doing it," Pinto added. "I hope the referee watches him very closely.
"I would like FIFA and the referee to watch out because it is very important and can have a huge influence on the result."
"Maybe he would have to leave the field because he gets two yellow cards for diving" - Jorge Luis Pinto
Ravshan Irmatov of Uzbekistan will be taking charge of the match and Pinto hopes he is brave to book Robben should he dive.
"That may be the most logical solution," he said. "Maybe he would have to leave the field because he gets two yellow cards for diving.
"Why not? That could happen. I want to trust the referees. Let's see what happens."