Carlos Alcaraz competes in the second round of the US Open. (Source: Getty)

Alcaraz did not get to experience a real battle in the first round, only having to play one set against Dominik Kopefer before the German withdrew due to injury. So it was not until the second round that the defending men's singles champion faced his first challenge.

Alcaraz is the youngest number one seed in US Open history, he successfully defended 9 out of 10 break-points in the match against Kopefer, he also came back to win the third set after letting his opponent take the lead.

Harris was inconsistent, but the South African had brief spells of good play with some aggressive attacking play, especially heavy serves throughout the match, but Alcaraz also showed great defensive qualities from the back of the court.

Both players were a bit wobbly in the first service game, both having to save two break-points to protect their service games. However, Alcaraz quickly got into the rhythm of the match, the Spaniard broke the fifth and ninth games to win the first set 6-3.

Alcaraz is aiming for a second consecutive US Open men's singles title. (Source: Getty).

Harris started the second set with a clean serve game, but then he lost five games in a row, allowing Alcaraz to win 6-1. In the third set, Harris broke in the sixth game, leading 4-2, but Alcaraz broke back in the next game. When the score was not settled after 12 games, the two players had to play a tie-break in the third set. Alcaraz won 7-4 after having three mini breaks, losing two mini breaks.

Alcaraz improved his record to 55-6 this year (18-3 on hard courts) and is chasing his seventh title of the season and third Grand Slam title of his career. Alcaraz's next opponent will be Daniel Evans, the Briton who beat Botic van de Zandschulp 1-6, 6-1, 6-3, 6-3.

The US Open is a tough tournament, since Roger Federer won 5 consecutive titles (2004-2008), no player has been able to win the men's singles title two years in a row. Now, Alcaraz is the one who hopes to reap that success.