Arsenal keeper Szczesny misses Montpellier trip

Arsenal will be without first-choice goalkeeper Wojciech Szczesny because of an ankle problem for Tuesday's Champions League Group B opener in Montpellier.

Vito Mannone will again deputise, with 21-year-old James Shea on the bench.

Italian Mannone has played in goal for two games already this season in away games at Stoke and Liverpool and is yet to concede a goal.

Arsene Wenger has every confidence Mannone holds the "mental strength" to put his Champions League nightmare from last season behind him.

He produced a calamitous display in the defeat at Olympiacos last December, but a productive four-month loan spell at Championship side Hull built up the confidence of the 24-year-old once again and Wenger has no issue with throwing Mannone straight into the action at Stade La Mosson.

"Vito is very close (to the Arsenal number one jersey), and he gets another opportunity now," said Wenger as the squad prepared to leave Luton Airport.

"He has belief and he has the mental strength to deal with that."

Midfielder Abou Diaby (hip) was in the 18-man squad which left Luton on Monday afternoon, but Russian winger Andrey Arshavin missed out.

Tomas Rosicky (hamstring), Jack Wilshere (ankle) and Emmanuel Frimpong (knee) all continue their rehabilitation along with defender Bacary Sagna (broken leg).

Meanwhile, Wenger has said Olivier Giroud's struggles in his first few games for Arsenal are normal and the French striker will improve after scoring his first goal.

Arsenal start their Champions League campaign on Tuesday at Montpellier, the club Giroud helped win the French title last season by finishing as the league's top scorer with 21 goals.

The France striker has not scored for Arsenal yet and started last weekend's match against Southampton on the bench, with Wenger preferring Gervinho in his attack.

Wenger refused to say if he would start Giroud at Montpellier but Gervinho's presence by his side for the news conference suggested that the Ivorian could be chosen again.

"The play is really different in England, especially for the forwards," Wenger told a news conference.

"Discovering the Premier League is always a shock because you have more collisions, more contacts. So it takes a bit longer for the forwards than the others to adapt to the English football. But I am a patient."

Wenger suggested that Giroud just needed one goal to get going.

"All forwards enjoy cycles. But sometimes, a goal is enough to trigger everything."

Montpellier centre back Mapou Yanga-Mbiwa said Giroud would not find the net against his former club.

"For him, it would be great to shine in front of his former fans. But I already told him that, unfortunately, he would not score tomorrow," Yanga-Mbiwa said.