The 17-time Grand Slam champion from Switzerland was left as red-faced as his country's flag after his opponent, Grigor Dimitrov, offered a young boy from the audience a chance at duelling with the great Federer.

The Swiss champ was playing the Bulgarian in a BNP Paribas Showdown match in New York on Tuesday when Dimitrov allowed the young kid, wearing jeans and a hoodie, a chance to play a point against arguably the greatest tennis player ever.

After confidently returning Federer's serve with a forehand, he then follows it up with another forehand and a backhand before lobbing the Swiss master after he approached the net. Dimitrov and others in the audience raise their hands in amazement and joy as the lob lands perfectly inside the baseline.

The grinning kid high-fives the Bulgarian before returning to the stands. Federer is seen biting his shirt in embarrassment after the unexpected tennis lesson.

Dimitrov was obviously inspired by the young kid's talents, winning the match 6-2, 1-6, 7-5.