With the glamour of a European semi-final against Barcelona now on the horizon and the quest for an FA Cup final spot ongoing, the danger is Liverpool could become wrapped up in the glory games and fail to deliver in the Premiership.

But Houllier was adamant in the wake of last night’s stunning UEFA Cup quarter-final victory over Porto that Liverpool will stay focused.

"Trust me. They will not be allowed to become sloppy," he promised.

"They will concentrate fully on all the league games, have no doubt about that."

Liverpool will be without ankle injury victim Nicky Barmby against Derby - the midfielder is also ruled out of England’s squad - and could well bring in Emile Heskey, Jari Litmanen and Christian Ziege.

Those who do play will have the words of down-to-earth Houllier ringing in their ears.

He said: "To me the Derby game is the most important. We lost our last league game at Leicester and we definitely need to produce a performance.

"If we were to win three cups and not qualify for the Champions League I would be very disappointed.

"So we must deliver in the Premiership. Trust me, they will concentrate on the right games - one at a time.

"The way things are going we cannot afford to slip up in the league. It’s intense, and the demands are tough in the Premier League.

"We have a European semi-final, and it’s a very exciting draw. But there can be no greater rehearsal for such a match than tough league games.

"When we went to Roma and won we had played at Sunderland the game before. That was the perfect way to prepare for a European tie."

Houllier believes any campaign can still go off the rails in the final two months and added: "We are at the turning point of our league season.

"It is always crucial that you pick up points in March and April that is the most important time.

"There is no point in having a great cup week and then losing a league game."

Houllier’s words are echoed by German midfielder Dietmar Hamann, as Liverpool bid to claim a second or third-place finish in the top flight.

"I know a lot of people are suggesting that our league form will suffer with all the cup games we’ve been playing, but I don’t agree," said Hamann.

"We’ve got quality players to come in and replace anyone who is feeling the strain of playing too many games. The league is still our main priority, so we won’t be letting our form dip."

Everything Liverpool have strived for this season could be decided in a jam-packed three weeks next month.

Houllier allowed himself one fleeting concession to the clashes with Barcelona when he said: "We are a match for anybody on our day.

"I know Roma didn’t particularly fancy playing us and I would think that that would be the same reaction around Europe."

Chief executive Rick Parry added: "This is a dream draw. It is what European football at the top level is all about.

"But we have a good chance. Nobody thought we would do so well against Roma, and they are one of the best teams around in Europe this season.

"We were excellent against them, so the Barcelona games will be great occasions."