He... erm ... pre-programmed it.
As the wide-eyed Finn scrambled for a seat and harness and found himself wishing for a number of very large, soft pads, Chewbacca groaned his readiness. Han studied the readouts before him. The Wookiee raised a hand over his own console. “And…” Han followed the declining fractions intently. “Now!”
Human and Wookiee hands flew over the main console, supplementing as best they could the approach and landing information they had preprogrammed into the Falcon’s instrumentation. Not unexpectedly, more than one last-second override was required in order to make the ship do something that was against its nature and perform maneuvers for which it had never been designed.
Most of his work at the console seems to be aimed at stopping the ship from aborting the approach rather than actually timing the landing.
