Liverpool had a stormy passage to the quarter-finals of the UEFA Cup here last night after the Roma team erupted in fury after being deprived of the chance to equalise on aggregate when the Spanish referee apparently awarded them a penalty only to change his mind in the space of a 10-yard stroll to the byline.

Liverpool now have a quarterfinal in two weeks' time against Porto, who went through 4-3 on aggregate despite being beaten 2-1 in Nantes last night.

By winning the tie's first leg 2-0 in Rome's Olympic stadium last week, Liverpool convinced all but the most pessimistic among their own support and the most optimistic among their opponents' that this second meeting of two great clubs was something of an irrelevance.

Of course, neither Houllier nor his opposite number Fabio Capello would publicly subscribe to that theory for one of the managerial brethren's unspoken rules is that there is no such thing as a lost cause. That said, on paper his team had a makeshift look to it with injuries, suspensions and sheer fatigue taking their toll. Houllier must have been delighted to see a Roma team-sheet which did not boast the names of Totti, Emerson, Cafu, Aldair nor, most mystifyingly of all, Gabriel Batistuta.

Even though his resources had been stretched to the limit, Capello could offer the famed Argentine forward nothing more appealing than a place on the bench.

Michael Owen's brace had settled the issue in the Eternal City and while he will have been delighted to win favour last night it will probably have crossed his fertile mind that the omission of one Robbie Fowler suggested that he was more or less guaranteed a place in Sunday's Worthington Cup final line-up. Then again, with Houllier, nobody ever really knows.

There was certainly a good deal more steel to Roma second time around, which is to say the iron fist was withdrawn from the velvet glove and used at a very early stage.

Curiously, the man in red targeted for the Latino rough stuff was the centre-back Sami Hyypia who had already been kicked from pillar to post before Vincenzo Montella was cautioned for felling him with a trailing elbow.

The early play was all Roma's and the suspicion that Liverpool were, perhaps, struggling to hold on was lent credence by the ease with which the Italians mounted and sustained attacks laden with promise.

But Liverpool's precision back four was again mean and ruthlessly efficient, coaxing the Roma strikers forwards before springing the offside trap.

Well, most of the time, anyway. As Roma's dominance became more pronounced, their industry in midfield began to produce chances, the best falling to Marco Delvecchio who steered hopelessly wide on 20 minutes after Hyypia and company had been undone by Hidetoshi Nakata's splendid pass.

Despite being surrounded by home comforts and many friends, Liverpool were decidedly ill at ease.

Liverpool had to wait until eight minutes before the interval for the glimmer of an opening, and then two arrived in quick succession. After Roma's goalkeeper Francesco Antonioli had thrown himself down marvellously to halt a Christian Ziege free-kick, Owen found space inside the area only to screw his drive wide.

If, during the recess, Houllier instructed his side to attempt to alleviate the stifling pressure by pushing forwards instead of simply falling backwards, they obviously were not listening.

The second period was little more than a mirror image of the first, Roma rolling forwards like a sea mist, Liverpool clinging on grimly.

And then, unexpectedly, the perfect opportunity for Liverpool to put the game and the tie to bed. On the hour, Jonathan Zebina was adjudged to have impeded Emile Heskey deep inside the Roma area. The referee Jose-Maria Garcia-Aranda awarded a penalty, generously it must be said. Owen volunteered but his kick lacked venom and was wayward, and Antonioli saved with ease.

Then came the disputed penalty and the mayhem but Liverpool are through to the quarters.

LIVERPOOL: Westerveld, Babbel, Hyypia, Henchoz, Carragher, Ziege, Hamann, McAllister, Barmby (Fowler 81), Heskey, Owen (Smicer 67). Subs Not Used: Arphexad, Diomede, Vignal, Wright, Navaro.

ROMA: Antonioli, Zago, Assuncao, Samuel, Zebina , Nakata, Tommasi, Candela, Rinaldi (Guigou 59), Delvecchio (Batistuta 59), Montella (Balbo 79). Subs Not Used: Lupatelli, Di Francesco, D'Agostino, Bovo. Sent Off: Tommasi (85). Booked: Montella, Assuncao, Zebina , Tommasi, Guigou. Goals: Guigou 70.

Referee: Jose Maria Garcia-Aranda (Spain).