The 17-year-old was playing her first Grand Slam quarter-final, but under 4-0 in the second set, a frustrated Gauff broke her racket on the clay court after committing a double foul.
Gauff brought his opponent close in the opening set, with Krejcikova needing a dramatic tiebreak to gain the upper hand in the match.
In the second set, the Czech increased the pressure on her youngest opponent, winning the first five matches with no response.
But the American showed experience in believing her age, saving more match points and winning three straight games to make things nervous before Krejcikova claimed the decisive ninth game of the second set to reach the semi-finals.
“Already for me this is something I would never have dreamed of. I was really playing a great game and Coco is incredible: she is 17, she is incredible”.
Both players were playing their first career singles Grand Slam quarter-finals. By reaching the quarter-finals, Gauff had become the youngest woman to compete in a Grand Slam quarter-final since 2006.
Despite her age, 17-year-old Gauff didn’t look out of place on the big stage at Court Philippe Chatrier.
The number 24 seeded 3-0 and 5-3 in the opening set, but Krejcikova reacted, saving five match points before taking the 72-minute set.
Gauff singled out the defeat of the first set as the turning point of the match.
This really seemed to kick off world number 33.
He looked much more comfortable in the second set, manipulating the ball at will, with Gauff struggling to gain momentum.
And leading 5-0 in the second set and needing just one more match to reach her first Grand Slam singles semi-final, which seemed like a formality for Krejcikova with Gauff looking shaken.
However, Gauff has shown remarkable strength and resilience in saving multiple match points to win three consecutive games and suggests that a previously unthinkable recovery may be possible.
But that was not the case and in Krejcikova’s sixth match point the Czech won the match after an hour and 50 minutes.
Krejcikova believes part of her single success is due to a change of perspective during the Covid-19 shutdown.
“It just occurred to me. I’m like, well, I go and play tennis and lose, but there are actually people who are losing their lives. I felt more like, well, relax because you are healthy. Appreciate this and enjoy. the game. You can do something that maybe other people would like to do, but can’t. “
Krejcikova will face reigning champion Iga Swiatek or Greek Maria Sakkari for a place in the final at Roland Garros.