How to silence notifications without unlocking my phone and swiping them open?

Hi,

I am an owner of Nexus 5X. Whenever a notification shows up on my screen and my phone starts to play the notification sound, I have to either
1) Unlock my phone and open notifications tray.
2) Turn my screen on (showing lock screen) and swipe any notification open.

Previously I was able to just turn my screen to silence notifications. Is there a way to restore the old behavior?