The 18-year-old had to fight his way back from two sets to one deficit and went on to win 5-7 6-1 5-7 6-2 6-0 to become the youngest man in the Open era to win the US Open. reached the last eight.
“I’m super excited to be in the grand slam in my first second week, so it’s great for me,” Alcaraz said after the game. “It’s a dream come true.
“It’s very difficult to play matches like this, to play fifth sets. I hope to play more second weeks, play more grand slam quarter-finals. I didn’t expect to play quarter-finals here. So I think it’s a very good performance from me in these matches.”
That shocking win over Tsitsipas – which Alcaraz secured in a nail-biting fifth set tiebreaker – added to what was already an incredible breakout season for the youngster.
Alcaraz won his first ATP Tour title in July, beating Richard Gasquet in the final of the Croatian Open and also reached the third round at the French Open.
A teenage revolution in Flushing Meadows
On the women’s side of the draw, the teens continue to take over the US Open as 19-year-old Leylah Fernandez, who is celebrating her birthday on Monday, came off a set-down to beat former US Open champion Angelique Kerber 4-6 7- 6 6-2.
Fernandez, who had never made it past the third round in a grand slam before, now faces Elina Svitolina for a place in the semi-finals.
“I had to pinch myself a bit to see it really happen, but I knew that my tennis, my tennis level is there,” she said after the game.
“It’s only a moment of time, chance, and I’m glad I got this chance now and that I was able to show what I can do for these players. Even if I had lost I would have been proud of myself with the way I played, the way I fought.
“I was lucky enough to take the win today and get this experience. It’s my first quarterfinal in a grand slam. I’m just going to enjoy it 100% and tomorrow will be a new day.”
Alcaraz and Fernandez can still be joined by another teenager in the quarter-finals, and 18-year-old Briton Emma Raducanu will face Shelby Rogers in the last 16 on Monday.