Arsenal's attack missing cutting edge, says Wenger

If Arsenal are to have any chance of overturning a 2-0 deficit against Barcelona in the Champions League next month they must be sharper in front of goal, says manager Arsene Wenger.

They worked hard to keep the world's most fearsome attacking trio of Lionel Messi, Luis Suarez and Neymar relatively quiet until the 71st minute of Tuesday's last 16, first-leg tie but by then they had spurned two excellent chances to take the lead.

Alex Oxlade-Chamberlain was the culprit in the first half, anxiously shooting straight at Barcelona goalkeeper Marc-Andre ter Stegen, then Frenchman Olivier Giroud failed to convert the kind of close-range header he regularly dispatches.

They are the sort of opportunitites that must be taken in the return at the Nou Camp on March 16 when Arsenal face what many pundits think is 'mission impossible' after Messi showed how it should be done with two late goals at The Emirates.

The Argentine's first strike followed a clinical counter-attack and his second from the penalty spot in the 83rd came after he was brought down by substitute Mathieu Flamini.

"We had an unbelievable chance in the first half and the way we finished our chances is a problem," Wenger told reporters after his side's demoralising defeat.

"Technically we are not precise enough. I feel that in the final third at the moment we are missing something."

Arsenal face a sixth consecutive last 16 defeat in Europe's elite club competition and the evidence suggests that when they play the really big guns of European football they lack the killer instinct in front of goal.

Their keeper Petr Cech knows what is takes to win the Champions League, having done so with Chelsea, and must have winced as his team mates fail to score before he was finally beaten by Messi for the first time in his career.

"I thought we did really well until the first goal. We had some opportunities and we should have scored," Cech said.

"I think the only thing we didn't fulfil was that we didn't score. If you play one of the favourites to win the Champions League and you have a chance, you need to find a goal."

His fine save from Neymar's powerful header in stoppage time at least limited the damage, and Cech insisted they would go to Spain believing they could triumph.

"It is a difficult deficit to overcome but 2-0 is not 5-0 and we have 90 minutes with a chance," he said.