LONDON • A strange encounter, but an utterly beguiling one, where anything that could go wrong for Arsenal did go wrong.

They had 78 per cent of the possession, seemed set for a landslide when they eased ahead; cast themselves into the abyss with some schoolboy defending; missed a penalty; hit the post; missed an open goal; lost two players to injury and slunk back to North London in fourth place when they could have topped the Premier League.

Arsene Wenger described Arsenal's 2-1 defeat at West Bromwich Albion on Saturday as the "perfect nightmare" after midfielders Francis Coquelin and Mikel Arteta added to his injury woes.

Arteta's own goal, coupled with a late penalty miss by Santi Cazorla, ended the Gunners' six-match unbeaten Premier League run and dented their title challenge.

And Wenger, already without Alex Oxlade-Chamberlain, Theo Walcott, Aaron Ramsey and Danny Welbeck, suffered further setbacks when he lost midfielders Coquelin to a knee problem and Arteta to a recurrence of a calf injury.

Both players will be assessed and are in doubt for tomorrow's Champions League home match against Dinamo Zagreb, which Arsenal must win to stand any chance of staying in the competition.

"It was a very bad afternoon for us," said Wenger. "But give West Brom credit for fighting. They fought with 100 per cent commitment.

"Our defending at that level was very, very poor."

Wenger refused to blame Cazorla for his missed penalty, which came amid confusion, as it seemed referee Mark Clattenburg had ordered a retake for encroachment.

As it turned out, Clattenburg had penalised the midfielder for taking two touches as he slipped.

Arsenal were consigned to defeat despite an early goal from Olivier Giroud who, like France team-mate Laurent Koscielny, played eight days after being caught up in the horrific Paris attacks while playing for France in the friendly against Germany at the Stade de France.

Wenger said that he had no doubts about fielding either player, citing their professionalism. "They were highly focused and had a desire to play," the manager said.

West Brom manager Tony Pulis, whose side drew level through James Morrison before Arteta's own goal, acknowledged that his players had gained victory despite not being at their best.

"It's a great result. The lads deserve it for the effort they've put in," he said. "But we've played better and done better and not got the results."

THE TIMES, LONDON, AGENCE FRANCE-PRESSE