The Reds finished the season in fifth place whilst Houllier's signings struggled to justify themselves. The Reds boss admits that he expects to see more from all three players next season as Liverpool launch another bid for the Premiership title.
Houllier, speaking to the BBC, said: "I still have faith in these players. I think they will be good signings for Liverpool. Perhaps I should have taken this into account because they had had a very long and gruelling season.
"Diao and Diouf played in the African Nations Cup in February and then the World Cup in June. If you then take into account that they had a very successful and quite long World Cup campaign with Senegal, I think maybe I should have been more careful with them.
"But Diouf adapted well as the season went on. He scored six goals and had eight assists. He is also very young and will improve. Diao did well when he played, especially in the derby at Everton when we won after he came on as substitute.
"Bruno Cheyrou was unlucky because he was injured in November for six weeks, but he showed at times he has the quality.
"He has got the skill and the eye and he just needs to come to terms with the physicality of the English game. I have total faith in Bruno." 