The robbery took place at the eCloud shop in Southey Green Road, Wadsley Bridge at around 4pm on September 25 this year.
During a hearing at Sheffield Crown Court today, prosecutor, Louise Gallagher, explained how defendant, Ashley Hobson, struck up a conversation with his 21-year-old victim, before robbing him of his Apple Watch.
"He used his left hand to grab the watch, with quite a lot of force, and this caused some pain to the victim, who at the time of making his statement was wearing a support bandage," said Ms Gallagher.
After stealing the watch, Hobson, aged 35, fled the scene.
His victim obtained CCTV footage of the robbery from the shop's owner, which he then posted on Facebook later that day in a bid to trace Hobson.
But the victim's mother did not want to wait for witnesses to come forward, and started searching for Hobson herself.
"His mother started going around all of the shops in the area looking for Hobson," said Ms Gallagher.
The court was told how the young man's mother tracked Hobson down at a nearby chemist, and found him wearing the watch.
Ian Goldsack, defending, described how the woman punched Hobson 'squarely to the jaw,' which led to the police being called and to Hobson being arrested
Mr Goldsack claimed the victim's mother inflicted more harm against Hobson, of Holgate Road, Parson Cross than he had caused her son during the robbery.
But this was not accepted by Recorder Christopher Knox, who said he believed the woman's actions were 'justified' and had led to Hobson being brought before the court.
He continued: "Her actions were incredibly public spirited and praiseworthy.
"The court admires her determination to take you down and bring you to justice."
In mitigation, Mr Goldsack said Hobson was a struggling drug addict who went into the shop with the intention to shoplift, and only decided to rob the watch when the 'opportunity arose'.
Hobson, who has an extensive criminal record of 119 offences from 89 convictions, pleaded guilty to one count of robbery at an earlier hearing.
Recorder Knox sentenced Hobson to 16 months in prison.