The pair have both expressed a disappointment that they have not had more chances to impress in the first team this season and Babel has openly questioned the Liverpool manager's selection decisions, suggesting he wants to go on loan to Ajax in January to improve his chances of playing for Holland in the World Cup finals next summer.
The Dutchman even went to the extent of claiming that promises had been broken by Liverpool over the amount of first-team opportunities he would have this season, while Spanish international Riera has also failed to impress. But Benitez is unmoved by the pairs' concerns.
He said: ''Albert and Ryan both want to play. They play in the same position and so have to compete with each other, which is good for us. The message is very simple. On the pitch all of the players have to prove something.
''Ryan knows he cannot go now, so he has to impress. He is a good player and we know he has talent. It's important for us to talk with him and see how he progresses over these months.
''With the World Cup at the end of the season the majority of our players will want to impress and if they do well in each training session they will have more chances.''