ARSENE Wenger was pleased by the way Theo Walcott shrugged off a bad start in Sunday’s North London derby to play a key role in Arsenal’s win.The England international endured a frustrating opening period against Tottenham, who had racked up a two-goal lead by the 34th minute thanks to goals from Louis Saha and Emmanuel Adebayor.Bacary Sagna and Robin van Persie pegged Spurs back before half-time, although calls remained for Walcott to be replaced at the break.However, the winger followed up a Tomas Rosicky effort with a second-half brace to complete a resounding 5-2 victory at the Emirates Stadium."The crowd were starting to get on his back and you wonder if you’re doing him a favour if you leave him on,” Arsenal boss Wenger said of Walcott."Considering the rest of the team were high on confidence, I felt that he has the qualities that we needed - a player who can be direct, go behind the defenders. Nobody else is like that.”