The Gunners have conceded just once in three games since a March defeat at Tottenham left them seven points off their rivals in the race for the UEFA Champions League places.
Arsenal's defenders accepted the blame in the wake of that game, and neither Wojciech Szczesny nor Thomas Vermaelen has played in three straight victories since.
One of those came at Bayern Munich, while back-to-back Premier League wins mean Arsenal are now just two points off fourth spot.
"Everybody has realised that clean sheets win games a lot of the time," said coach Bould, who was credited with improving Arsenal's defence early in the season before last term's errors began to creep in.
"I'm hoping that the Tottenham defeat is the big turning point. We played really well on the day and I think we absolutely deserved more than we got.
"Two defensive errors and we got punished by good players and that's what happens."
A susbequent 2-0 win at Bayern was not enough to prevent a Champions League exit, but Bould said: "A big thing for us was getting the big result at Bayern.
"We're only the second team to have won there this season so it's given everybody a belief that we're doing all right. It was an important game for us."