Manchester City...0 Liverpool...1On a petrifyingly cold afternoon and in a match where ideas never stood a chance of germinating there were still green shoots of recovery. A Liverpool win was heartening enough but Gerard Houllier's players also witnessed the necessary evidence that their system can still work.

Others will regret seeing rigidity and prudence rewarded again but it is woolly-headed to suppose that Liverpool, in debilitating form, could suddenly be converted to flamboyance and virtuosity. They have yet to call a halt to the League failure which has seen them go 10 games without a win, but the defeat of Premiership opponents on an important occasion must be heartening.

There was a tight-fisted allocation of incidents in this FA Cup tie, but Houllier will rub his hands with pleasure as he thinks of all the things that never happened. There was no goal for Nicolas Anelka, the man he chose not to keep at Anfield.

Just as satisfyingly, El Hadji Diouf, whom he preferred to buy, did not suffer by comparison with the France attacker.

He threatened to score on the break, after Peter Schmeichel had gone upfield for a corner, hit the outside of the post with a cross, and then volleyed narrowly wide after the Manchester City goalkeeper, with a desperate clearance, had headed out to him some 40 yards from goal.

All of that happened from the 90th minute onwards in a fixture where the latecomers' single mistake lay in turning up at all.

There was some debate as to whether City's side were also on the premises.

"I tried to explain to the foreign players what it means in this country," said Kevin Keegan, referring to the tournament's heritage. "I might as well have saved my breath."

He was pained that the last FA Cup tie at Maine Road, before City's move, should have been a shuffling, leaden-footed business.

The only goal annoyed the manager in ways he had difficulty in explaining, even to himself.

With Vladimir Smicer preparing to deliver from the left, after 47 minutes, Marc-Vivien Foe threw up his arms, as opponents do when trying to distract a crosser and block his view.

Having chosen to do that, there could be no rational protest from the midfielder when the referee awarded a penalty as the cross hit Foe's right hand. Danny Murphy dispatched it slickly.

Keegan conceded that the decision was "technically" correct but did not permit that factor to stop him from castigating the official.

"I never talk about Uriah Rennie except to say I don't like him as a referee. Never have, never will," the City manager remarked, before giving withering advice to anyone requiring further information about the niceties of the penalty ruling.

"Ask Mr Rennie, he's a law unto himself. Ask his agent if you can have an interview with Mr Rennie."

It was the passionate, slightly muddled rancour of a disappointed man. He must have been agitated beforehand that illness and an Achilles injury had robbed him respectively of Richard Dunne and Steve Howey, but it was even more bruising to such an idealist that it was not the makeshift defence which let him down. City created next to nothing.

Chris Kirkland's one noteworthy save came when he blocked a 44th-minute effort from Anelka, who had sprung the offside trap to gather Eyal Berkovic's pass.

The Israel midfielder had only just come on, with Keegan unable to bear the wait until the interval to try to enliven his side.

That was testimony to Liverpool's effectiveness in imposing their scheme.

"We had to make sure first of all that we denied them in midfield," said Houllier.

In that area, Steven Gerrard continued to maintain sound form through sheer determination while he waits for his inherent vivacity to come to the fore once again.

Aid for Murphy also came from Salif Diao, who has been categorised unfairly as one of Houllier's dubious acquisitions.

His form has been better than that and Houllier reminded everyone that the Senegal midfielder, like the £10 million signing Diouf, was involved in a debilitating run to the quarter-finals of the World Cup last summer.

Perhaps, as he says, we will see the very best of these footballers only in the second half of the season.

In victory, Houllier knows that, for a change, there will not be a querulous reaction to his every word.

"I am very proud of the players' attitude," he said. "It is not a period in which things are going our way but today we showed strength, solidity and mental stamina. Our club have a tradition of success, of winning trophies, so we need (to start) performing at our level."

Liverpool, so often reviled as plodders, are finding that their happiest fixtures lie in the mercurial, knock-out environment of the League Cup, UEFA Cup and FA Cup.

Houllier would be happy to live with that paradox for months to come.

MAN CITY: Schmeichel, Wiekens, Mettomo (Berkovic 41), Distin, Jihai (Goater 70), Benarbia (Huckerby 85), Foe, Horlock, Jensen, Wright-Phillips, Anelka. Subs Not Used: Nash, Ritchie. Booked: Berkovic, Distin.

LIVERPOOL: Kirkland, Carragher, Henchoz, Hyypia, Traore, Murphy, Diao, Gerrard, Smicer (Riise 86), Mellor (Heskey 73), Diouf. Subs Not Used: Dudek, Baros, Cheyrou. Booked: Smicer, Traore, Murphy. Goals: Murphy 47 pen.

Referee: U Rennie (S Yorkshire)