Wenger boosted by Walcotts return for Saints clash
Arsene Wenger's side sit two points clear of second-placed Liverpool going into the meeting with Mauricio Pochettino's emerging side, who are just three points behind the Gunners in third place.
A defeat against champions Manchester United before the international break took the edge off Arsenal's impressive early-season form and a further setback against the Saints would raise more questions about their ability to sustain their challenge.
However, the break has provided Wenger's squad with the chance to regroup and allowed Walcott to regain full fitness after a two-month absence with a stomach injury.
And Wenger believes the England winger can provide his side with an added dimension when they face Walcott's former club at the Emirates Stadium.
"He is one of the players who goes behind the defence without the ball," Wenger said.
"Players who get behind the defenders are very important and Theo has that quality.
"Of course you miss a player like Theo. He had a good start to the season, he scored goals, he provided chances and had assists. He can always give you a different option in the game and that is of course vital.
"You always want to have a perfect balance. If you look at our results our balance was not too bad.
"But Theo has different qualities to other players and I am very pleased that he's back."
Arsenal centre-back Per Mertesacker should return on a high after his goal secured Germany's 1-0 friendly victory over England at Wembley this week.
And Wenger believes his side will also benefit from France's success in reaching the World Cup finals.
Olivier Giroud and Bacary Sagna were in Les Bleus' squad that overcame Ukraine in a play-off on Tuesday to reach the tournament in Brazil.
"I have a smile on my face because first it was a relief for France to go through," Wenger said.
"It's positive for France because it was a big relief and the country needed it.
"There is a lot of unrest between the French national team and the country since the last World Cup in South Africa, and that they could turn a situation like that in a positive way will help people to love the national team again."
There was more good news for Wenger as midfielder Jack Wilshere is expected to be fit after suffering an ankle injury on international duty with England.
Southampton have emerged as the season's unexpected success story and their progress was underlined by the inclusion of Jay Rodriguez, Adam Lallana and Rickie Lambert in the England squad for last week's friendlies.
Pochettino's side have performed well against the leading sides, including recording a victory at Liverpool, and the manager is planning a repeat success at the Emirates.
"I think it's going to be similar to the game against Liverpool because when we were playing them they were top of the league," Pochettino said.
"We always have to believe that we can get something positive out of every single game that we play.
"We believe that we can play a very good game and we can get a very positive result in this game.
"So far I think in the league Arsenal are showing the best football and they have been the best side.
"They're very dynamic and very quick and fast on the counter-attack. They have extraordinary players at their disposal."
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