Spurs supporter and journalist James Dickens claims the abuse was directed at Son by a spectator. He says that, when he confronted the fan, he was sworn at.
Dickens confirmed he is working with the club to identify the culprit, tweeting: “I’ve not experienced racism at football for about 15 years. But today at @SpursOfficial was hideous. Reported to stewards, confronted him myself.
“Spurs are looking into this now, and have been great.”
Tottenham found themselves in hot water last month after a fan threw a banana skin at Arsenal striker Pierre-Emerick Aubameyang, who is of mixed race.
The fan in question was fined and handed a four-year football banning order.