A top three finish would ensure automatic qualification for the Champions League rather than a risky qualifier.
"A few weeks ago third place looked unaccessible. But now, who knows? We don't know what is going to happen.
"All we know is that we will give everything we have to do well over the last 18 games," said Houllier. "It's a marathon, but each game within the marathon is going to be a sprint. We know what we have to do.
"The mood within the camp is outstanding and I am delighted with the mental strength the players have shown of late. We are on a good run at the moment and we want to keep it going.
"I am glad we have gone through a bad period because we have picked up qualities which will stand us in good stead for the rest of the season.
"We have stayed together during the bad run and shown great togetherness. The team bonding is brilliant and I am confident we will have a good second half to the season now that we are getting our injured players back."
