Arsenal 0, West Ham United 1.

Arsene Wenger admits the need for Arsenal to get their bid for a top-four finish in the Premiership has now become ''urgent''.

The Gunners suffered a third straight league defeat when relegation battlers West Ham became the first team to win at the Emirates Stadium.

It was an all too familiar story as Wenger's men created chance after chance, but could not find the back of the net and were then made to pay as Bobby Zamora struck in first-half stoppage time.

Despite still having a match in hand on the sides around them, fourth-placed Arsenal are now only two points ahead of Bolton, who visit the Emirates next weekend.

Wenger knows there is now little margin for further error in their remaining games, which continue up at Newcastle today.

''Routine in football does not exist. It is just always the consequence of the quality of your performances,'' said Wenger, on the expectancy of Champions League football again next season. ''Of course we feel we will do it and I am convinced we will. The situation becomes very urgent.''

Wenger added: ''Now we just think about regrouping, and not feel sorry too much and not be down too much because in two days we have a big game again.

''It is very hard, but the team is going through a patch where if we deal well with that situation we grow old very quickly.

''That is why it is very important that we do not let ourselves down and be too negative - there were a lot of positives and now let us show that again at Newcastle.''

Given the way they raced out of the blocks, Arsenal should have been out of sight by the time Zamora lobbed in what proved to be the winning goal.

West Ham goalkeeper Robert Green was a busy man, denying Cesc Fabregas inside 90 seconds and then keeping out efforts from Freddie Ljungberg and Tomas Rosicky, which really should have been put away.

When the England stopper was finally beaten midway through the second half, Fabregas saw his 18-yard strike come back of the underside of the crossbar.

Wenger accepted his squad - without injured captain Thierry Henry and Robin van Persie - had lacked a cutting edge.

''We know it can happen - but the way we lost it is very difficult to accept,'' said the Arsenal manager. ''It shows that in football, you need everything.

''It is good to have a good game, it is a good basis - but at the end of the day as well you need to have all the qualities that make a strong team, that is all part of a quality team.''

Hammers boss Alan Curbishley hailed his goalkeeper after the match and believes it will not be long before Green is back in the England squad.

He said: ''There have been games were we have not performed, and so not given ourselves a chance.

''But against Arsenal we had something to hold on to - and that was down to a fantastic display from Robert Green, along with some other great blocks.

''The rest of Robert's game has also improved, like his kicking and he is coming for crosses.

''He was in the England squad for the friendlies before the World Cup and then got injured.

''The other two chaps are also in relegation scraps, with Ben Foster at Watford and Scott Carson at Charlton, are both playing excellently.

''It has been a difficult time for Robert.West Ham bought him injured and he had to wait to get in the side. Then when he did get in, the results did not go so well.

''We have managed to keep a settled side over the last few games, and hopefully now that will build the confidence.

''I think we will all come out of it stronger - and hopefully that will be in the Premiership."