The Bafana Bafana star had to wait through a fortnight of quarantine following his loan move to from French side Amiens on transfer deadline day.
But Steven Gerrard spoke of his delight at having the midfielder available at last – and how he had been keeping fit while staying safe indoors.
The Rangers boss said: "It has been a long two weeks for him in quarantine on his own in the flat in Glasgow.
"He is desperate to be involved. He trained for the first time today, which was fantastic.
"We managed to get a running machine and a bike and some dumbbells to his apartment so he's been ticking over and doing a certain level of training but he will feel it today because the tempo was high.
"It is very exciting to have him available. He is happy, smiling and great to have him finally with us."
Rangers detailed the midfielder’s first day on social media – to the delight of many fans in his home country who have begun following the Ibrox club online in their droves after the transfer on October 5.
Zungu is included in Steven Gerrard’s Europa League squad so is eligible to be involved against Lech Poznan tomorrow night, but his lack of training and long wait to join his team-mates may make an early introduction to Ibrox unlikely.