expression "with a single swing / swoop of X"

Hello everyone,

How would you translate expression "with a single swing / swoop of X"

my only guess would be "uno ictu" but I am not 100% sure.

examples (to illustrate context):
1. brave knight cut off dragon's head with a single swing of his sword.
Eques fortis caput draconis (uno ictu??) gladii sui cecidit.

2. Strong lumberjack cut down a spruce with a single swing of his axe.
Validus lignator pinum uno ictu securis suae cecidit.

Thanks in advance for your time and help.