As shots reigned upon the Sunderland goal keeper Jurgen Macho and the crossbar prevented the deadlock being broken.
"We had 21 attempts on goal and they didn't have one," said Houllier. "People say we are boring but the statistics show we are second only to Manchester United in terms of shots on goal.
"I am disappointed for the players because they displayed so much energy. They showed they had overcome that setback in Basle.
"In a game like this where you have so much possession you would win nine times out of 10.
"They rode their luck and defended very well. I am sure Sunderland's goalkeeper got the man of the match.
"The only thing that was missing today was the goal we deserved for creating so many chances.
"I would be worried if we were not creating the opportunities. You have to remember our strikers are young and the best is yet to come."