The Gunners battled hard for a 1-0 win away from home against rivals Tottenham in the Premier League.
As they hoped to avoid slipping up further to Manchester City in the title race, Arsenal chose practicality over style on Sunday.
“It doesn't really matter how they got it, it was a great result for Arsenal,” Walcott told Match of the Day.
“They showed again that they can mix it up, because they played almost like a Jose Mourinho side to see the game out.”
“It was exactly the same (as Manchester City) here, even though they had some important personnel out, they are so well drilled and structured that they showed it doesn't really matter who plays, because they are all drilled the same way defensively,” Walcott added.
“That comes down to the work they do on the training ground. I was lucky enough to watch them in pre-season and the amount of coaching staff who are involved in each session is incredible.
“It makes the players' lives so much easier when there is that level of detail, with coaches that are literally there for each individual player.
“As a squad, they are getting the same message drilled into them on a daily basis, so I am not surprised anymore when they can grind out a result like this.”