Just two minutes into her first Grand Slam final - and just her eighth Grand Slam event - the 20-year-old marched back to her seat after breaking the Romania's serve with a blistering backhand.
Jelena Ostapenko became the first Latvian worldwide to win a major Grand Slam title and in doing so prevented Simona Halep from becoming the number one ranked women's singles player in the world. She's the first competitor - man or woman - to win make the French her first career title since Gustavo Kuerten accomplished that feat in 1997, the day Ostapenko was born.
Ostapenko also recovered from a break behind in the third set and finished the contest with a flashing backhand victor to become the first unseeded player to win the title since Briton Margaret Scriven in 1933.
Ostapenko hit 54 winners, but it wasn't just the sheer number - it was also the timing.
And then the fearless Latvian, Jelena Ostapenko, blasted victor after winner past Halep and worked her way back into the match. The unseeded tennis player really believes now that "anything is possible".
Money will no longer be a problem for Ostapenko, her mother and father or half-brother Maksim, who lives in Los Angeles. But I tried to play aggressive and everything turned my way.
Halep failed to climb atop the top place on WTA world rankings after suffering another defeat as she did in 2014.
At one point Saturday, it looked as if Simona Halep was on her way to her first ever major victory.
Confederations Cup, Portogallo-Messico 2-2: il romanista Moreno in gol
Il goal del Portogallo arriva però ugualmente, con un'azione rocambolesca, culminata nella conclusione fortunosa di Cedric . Prima del vantaggio di Quaresma , è la Var protagonista al 21' annullando il gol di Pepe in posizione si offside.
And then there was no looking back for Ostapenko as she continued with the thought of "nothing to lose". Her best prior finish at a Grand Slam tournament was the Round of 32 at the 2017 Australian Open.
- "I can not believe I'm the Roland Garros champion".
But Halep admitted: "I felt sick in the stomach about playing in this final so maybe I wasn't ready to win it". Keep it going because you are only a kid.
Spanish player Anabel Medina Garrigues has also been helping with coaching as she recovers from an injury. But I think I can walk just in the city and be relaxed. She deserved to win.
The opening set was still up for grabs and at 5-4, the Latvian serving to stay in the set, two unforced errors awarded Halep the chance to take the first lead in the final. She broke Halep at love in that opening game with a bolt of a backhand victor down the line.
With much of the pre-match conversation dominated by Halep's improved on-court attitude, Cahill was quick to say he was happy with her composure through the final. But also in the deciding moments, I think I played pretty well.
The Latvian pulled on level terms at 3-3 and then went ahead with a break thanks to a massive stroke of fortune when her backhand, which was going to land at least a foot wide, caught the net and dropped dead the other side. Hurts a lot, and I need time just to - I don't know.
The unlikeliest Grand Slam win in recent times was, of course, defined by a few astonishing numbers and facts.