London - Arsenal forward Theo Walcott believes the arrival of Petr Cech at the Emirates Stadium has made a huge difference to the Gunners' title prospects.
The lack of a truly top-class goalkeeper has been cited as one of the reasons why Arsene Wenger's team have not won the Premier League since 2004.
But the pre-season arrival of Cech from champions and London rivals Chelsea, meant that was no longer the case and the experienced goalkeeper made several fine saves in a goalless draw at Stoke last weekend that took Arsenal back to the top of the table.
"The mental strength in this dressing room's the strongest it's ever been," Walcott said.
"When you have the likes of Petr Cech coming in, he just enhances that. He's a leader.
"We've just got to look at him because he's obviously been at the top level and won many things. If we all have the belief he's got, we can push on."
Arsenal lead surprise contenders Leicester City on goal difference alone and England international Walcott said the battle to be crowned champions was shaping up as the most exciting in Premier League history.
"You can't tell what's going to happen, it's just so tight. With the amount of teams that could potentially win this league, it's probably going to be the most exciting Premier League for a neutral ever, I think," he explained.
"No one can call it but we're top and we can be proud of that at this moment in time."
There has long been a suspicion that Arsenal can be harried out of their preferred game by teams prepared to take a physical approach.
But Walcott, 26, was proud of the resilience his team-mates demonstrated at Stoke.
"We felt from the start physically we were up for the fight and the battle," he said.
"It's an improvement from previous performances here. We've got to be proud of that point."