Arsenal manager Arsene Wenger refused to criticise goalkeeper Manuel Almunia following their shock 3-2 home defeat by West Brom.
West Brom raced into a 3-0 second half lead thanks to goals from Peter Odemwingie, Gonzalo Jara and former Gunner Jerome Thomas before two late goals from Samir Nasri gave Wenger's side hope.
Almunia gave away a first-half penalty but then saved Chris Brunt's spot-kick only to spill Jara's shot into the net in the 52nd minute.
Arsenal's goalkeeping weakness was the subject of much debate in the summer but Wenger chose to stick with Almunia. And the Arsenal manager remained loyal to his keeper after his latest blunder cost the Gunners the chance to close the gap on leaders Chelsea in the Barclays Premier League.
Arsenal remain four points adrift of the Blues but Wenger was reluctant to put the blame on the luckless Almunia.
'I don't think it was down to one player,' said Wenger. 'I think our level of focus on the job was not right.
'I believe you can include all the defenders as well. They all made massive mistakes so it would not be right to blame one player more than any other.
'We came back, we didn't give up and that was the positive. We fought until the last second but we started too late and we have to learn from what happened. We cannot repeat that kind of performance.'
Arsenal now face a trip to Partizan Belgrade in the Champions League on Tuesday night but Wenger is still keen to keep teenage star Jack Wilshere under wraps.
The 18-year-old was outstanding in the 4-1 Carling Cup victory over Tottenham in midweek but was kept on the bench until the second half against West Brom.
Whoops: Almunia brings down Odemwingie to concede a penalty
'He has played many games recently and we don't want to burn him,' said Wenger. 'He played 120 minutes on Tuesday so I decided to give him a rest. I don't think the changes affected the team, it was the level of focus.'
Delighted West Brom boss Roberto Di Matteo saw his side climb to fifth place in the top flight thanks to their thrilling success at the Emirates.
Thomas, sent off in an altercation with Wilshere in a Carling Cup tie between the two clubs last year, ran Arsenal ragged all afternoon and scored the third but Di Matteo said all his players deserved credit.
It was West Brom's first win at Arsenal for 27 years and Di Matteo was justifiably proud of his men.
'To play the way we did at Emirates takes a bit of courage,' said Di Matteo. 'It is three points and fantastic for us. It is a difficult place for us to come and win but we hoped to get some points from the top four, the big teams, and it was good that we managed to get three today.
'Jerome was excellent, but not only him, the whole team played very well. We needed everybody to have a good performance.
'Arsenal have some quality players and managed to get two goals back but we tried to get over the line and the victory was deserved.
'In the first game against Chelsea we made some mistakes but we have tired to cut them out and we are doing that. It is combination of working individually with the players and collectively as a team.'
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