By the end of October the Gunners will have faced the Barclays Premier League's two bottom clubs - Norwich and QPR - and reached the halfway stage of their Champions League group after a home game against Schalke.
And Wenger knows that maximum points from those three games will be vital for momentum, while there is also a Capital One Cup tie at Reading to be squeezed into this month. Wenger told Arsenal Player: "In October the moment of truth starts for the team."
He continued: "The league establishes itself a little bit and the Champions League goes to decisive moments. Therefore of course, it's important to be decisive and convincing. The target is always the same [after an international break]. When they come back, we want to quickly focus on our own targets again and get the team back mentally on our next game.
"I believe that we'll work and the team, after our last performance at West Ham (a 3-1 win), will want to continue the good run and focus well."
Wenger will be without Theo Walcott for the trip to Carrow Road as the England forward has not recovered from the injury suffered against San Marino last Friday.
"He has an injury to his chest and lungs," Wenger added. "We have to treat that clinically.
"He's quickly short of breath when he makes an effort but it's bruising and that will heal. It's no major concern but it will take we think about two weeks to be back to a normal level."