Liverpool did enough on a rain-sodden night in Oporto to go into next week's second leg at Anfield all square. But after a match of little fluent football, they may regret not having secured an away goal, especially after Roma showed in the previous round that even a two-goal lead can be vulnerable.

At the tail-end of a day of unrelenting, often torrential, rain, even the most cultured of feet were prone to error on a playing surface which favoured the artisan more than the aristocrat.

The Antas stadium pitch was sodden, and the tie only went ahead after the Italian referee, Pierluigi Collina, had undertaken a thorough examination two hours before kick-off.

But, an ability to adapt to terrain and climate is an attribute not to be lightly dismissed, and over the past few months Houllier's team has proved itself to be smart enough to assess and then modify without apparent discomfort: men for all seasons, indeed.

As in all four previous four away games in this competition, Houllier went with two forwards, the victim of the rotation system this time was Emile Heskey, relegated to the substitutes' bench to accommodate a front pairing of Michael Owen and Robbie Fowler.

With Christian Ziege adding class, if not pace, down the left side of midfield and Vladimir Smicer a creative outlet down the opposite flank, Liverpool attempted to carry the game to opponents who have a deserved reputation for football of a cavalier nature.

Liverpool played intelligently early on, distributing the ball sensibly and, most significantly, jealously guarding possession.

Curiously, on an evening which almost seemed to have been designed to suit the predatory forward, chances were at a premium.

Indeed, the game had crawled - at a snail's pace - to its 24th minute before there was even a hint of an opening. When it came it fell Liverpool's way and should, probably, have been converted.

Fowler's lobbed pass set Owen free, but he could do no more than steer his shot into the stomach of goalkeeper Sergey Ovchinnikov after he had comfortably outpaced Jorge Andrade.

Porto's lethargy became more pronounced as the opening half wore on, Liverpool drawing strength and taking comfort from their hosts' inability to change, with any speed, the direction of their infrequent attacks.

The interval beckoned before Porto seriously threatened to embarrass Liverpool, Sander Westerveld saving well from Carlos Chainho after Anderson Deco's pass had forged an opening.

Porto, you suspect, were on the sharp end of a half-time rollicking, for as the rain continued to fall from leaden, heavy skies, their football - at last - began to hint at a sense of urgency.

They even began to fashion openings; a half-full stadium was agog with anticipation.

The Portuguese might have gone in front after 47 minutes had Stephane Henchoz not stepped in very smartly to lift the ball off the toe of Jesus Pena as he shaped to turn home a Chainho cross from the right.

Steven Gerrard almost lifted the evening up out of the gutter on the hour with a fine drive from distance.

FC PORTO: Ovchinnikov, Jorge Costa (Aloisio 59), Nelson, Paredes, Secretario, Deco, Drulovic (Candido Costa 75), Andrade, Chainho, Capucho, Pena. Subs Not Used: Espinha, Santos, Maric, Romeu, Clayton. Booked: Paredes.

LIVERPOOL: Westerveld, Babbel, Henchoz, Hyypia, Carragher, Ziege (Murphy 55), Hamann, Gerrard, Smicer, Owen (Barmby 79), Fowler (Heskey 69). Subs Not Used: Arphexad, McAllister, Diomede, Wright.

Referee: P Collina (Italy).