Liverpool stand on the brink of the UEFA Cup semi-finals after a night of dogged defiance at the rain-drenched Estadio das Antas.

Porto, a 'European power' for a decade, were easier to hold in check than Liverpool had expected.

But that did not mean the Anfield men were not called on to run, battle and fight for every inch on a terrible night of driving rain.

But the rock on which they are building their current success, a solid back line and sterling performances by the exceptional Didi Hamann and Steven Gerrard, gave Liverpool the foundation for a fine result.

They now have a golden chance next Thursday in the second leg to finish the job and send Porto packing.

There were determined heroes everywhere - Sami Hyypia and Stephane Henchoz at the back, while Robbie Fowler and Michael Owen ran themselves ragged up front.

Boss Gerard Houllier can be more than delighted with his men, who reduced Porto to impotency, while their dangerman Jesus Pena went missing for long periods.

Liverpool clearly wanted a same-again European away day, based on the defensive strength and depth that had carried them to unexpected successes in Rome and Athens during this run to the quarter-finals.

Boss Gerard Houllier opted for the strike partnership that did so well in Rome - Owen and Fowler - while bringing back Vladimir Smicer and Christian Ziege.

The Portuguese side are not enjoying one of their better domestic seasons as they languish in fourth spot, five points behind leaders and bitter local rivals Boavista.

They went with their expected 4-3-3 formation with free-scoring Pena leading the line in a side that included former Aston Villa full-back Fernando Nelson with ex-Newcastle midfielder Silvio Maric on the bench.

A minute's silence was observed before the start, as Liverpool players wore black armbands and laid flowers around the pitch in memory of those who who had died in the bridge tragedy close to this northern Portuguese port.

In difficult, drenched conditions, Liverpool were soon on the defensive as Porto's ball players took control, Carlos Chainho, Anderson Deco and Carlos Secretario dictating the flow.

There were times when Liverpool conceded possession too quickly and it meant considerable running and covering for Gerrard and Hamann, while Jamie Carragher was put under intense pressure down the right by Capucho's penetrating runs.

But such was the initial hold on Pena by Hyypia, the Portuguese produced just one shot in the opening half.

It took Liverpool a while to come out of their shell, but on 20 minutes they created their first chance when Smicer, Carragher and then Owen cut through on the left only for the latter's dangerous cross to be hacked away from the six-yard box.

Four minutes later Liverpool created their first real opportunity when Fowler's instant lay-off sent Owen scampering in on goal behind Jorge Andrade.

But keeper Sergei Ovchinnikov narrowed the angle well and Owen's shot on the run went straight into the Russian's chest.

Porto hit back when from a corner, the ball was not cleared on two occasions and it ended with Nelson drilling a 20-yarder wide of the far post.

Porto were playing the game at the sort of pace Liverpool were happy with and it gave them time to regroup and organise their defence.

Liverpool keeper Sander Westerveld was finally called into action on 39 minutes when space opened up down the middle for the first time.

Deco's pass found Chainho 20 yards out and his drive was beaten away by the Dutchman.

Porto started the second period with more obvious venom and created an opening within minutes.

Capucho got the ball in from the left with a dangerous low ball and a combination of Henchoz's excellent saving tackle and Westerveld's block kept Pena out.

Porto had clearly been given a talking-to at the break and tried to increase the pace. Pena then found Cahinho with a clever pass and the midfielder cut across Henchoz before drilling a low shot that Westerveld held low down.

Ten minutes into the second period Ziege was withdrawn and Danny Murphy injected into midfield to provide fresh legs and lungs, while four minutes later Porto lost their experienced defender Jorge Costa with an ankle injury, Pires Aloisio taking over.

But Porto's injection of pace soon slackened and Liverpool were quick to take advantage.

Ovchinnikov needed to be swiftly down by his post to touch away a fierce Gerrard drive after a Babbel free-kick had been headed out to the young England midfielder.

On 67 minutes Pena finally slipped away from his multitude of markers and should have put Porto ahead. Deco's pass put him in behind Babbel, but a hurried cross-shot skidded well wide from a clear-cut opening.

Emile Heskey was thrown into the fray for Fowler, the skipper having turned in many yards of unselfish covering and running.

Nicky Barmby was next off the bench, taking over from Owen as Liverpool sought to further bottle up the midfield.

Porto then found their last reserves and Deco saw a 25-yarder skim across the box and inches wide of Westerveld's far post.

Teams:

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.

Att: 21,150

Ref: P Collina (Italy).