Pause iTunes with the spacebar while the Mac is locked I must be missing something as Google turned up nothing on this and I can't be the only one annoyed by this:

I have a MacBook Pro running Sierra 10.12.6.  I have iTunes on playing music all day for my work day, and frequently do work on a 2nd different computer.  After 15 minutes, my Mac automatically locks and starts the screensaver.  I mainly use the spacebar (on an external bluetooth keyboard) for Play/Pause in iTunes.  

The issue is that once the Mac is locked, the spacebar no longer pauses iTunes.  So I have to unlock the Mac just to pause music.  

Is there any way around this?
You can use the Play/Pause key (F8) on the keyboard to start/stop the playback. You can also play the previous track (F7) and the next track (F9), as well as adjust the Volume: mute (F10) decrease (F11) and increase (F12).