The fan came to Rohit Sharma, who was standing at the slips, and touched the opener's feet. The incident happened when Vernon Philander had just walked in after the dismissal of Senuran Muthusamy.
It was the third such incident in the ongoing South Africa tour of India. In the first Test at Vizag, a fan shook India skipper Virat Kohli's hand and tried to take a selfie with the on-field cricketers.
Earlier during the 2nd T20I between the two teams in Mohali, the proceedings were interrupted twice as fans entered the field.