João Fonseca has definitively introduced himself to the world as the latest teen sensation in men’s tennis by upsetting No. 9 seed Andrey Rublev 7-6 (1), 6-3, 7-6 (5) in the first round of the Australian Open.

Fonseca has long looked like a star-in-waiting. Under pressure in his first Grand Slam set, he delivered beyond those lofty expectations

Endless queues outside Melbourne Park's 1573 Arena on a sunny Thursday afternoon gave casual fans the impression that a Grand Slam champion was in action, but a quick peek inside revealed the carnival atmosphere and explained the interest.