Soon enough, Ostapenko was holding her silver trophy - remember, the first she's ever won on tour - while listening to the Latvian national anthem ring through a Grand Slam stadium after a singles final for the first time.
The 20-year-old, ranked 47, had never been beyond the third round at a grand slam before nor won a senior title.
On Saturday, when she might have shown signs of nerves in the biggest match of her life, Ostapenko began with three huge winners in the first game and ended with a backhand return victor rifled down the line before Halep had moved. 'I knew she had it inside of her, it's just trying to get her to dig down deep and really commit to it and she's been great since.
The last player to lift the French Open as their first crown was Brazil's Gustavo Kuerten in 1997 - on the same day Ostapenko was born. "There are no words".
"Of course I will probably now will have more pressure and attention, but I'm going to try to deal with that", she said. "I would be surprised if she came out and hit winners all over the court like she has been". "Jelena Ostapenko did it right here this week", Martina Navratilova, a victor of Grand Slam singles title, told the Tennis Channel.
Both the women were finding it hard to hold serve: Ostapenko won eight of 19 break points in the match while Halep took 6 of 16.
And then there was no looking back for Ostapenko as she continued with the thought of "nothing to lose".
Ostapenko's carefree attacking tennis ultimately proved too strong for the consistency and experience of Halep, with the favourite helpless by the closing stages.
But Ostapenko had made almost as many errors and the challenge for her was to keep the ratio in her favour.
She refused to accept she might not even make it to Paris after suffering an ankle injury a week before the tournament and then fought back from a set and 5-1 down against Elina Svitolina in the quarter-finals. "That's why I work 20 years and played 20 years to have this moment", said the 25-year-old, who will rise to No2 in the rankings on Monday and will lead the Porsche Race to Singapore standings.
There was nothing lucky about the way she struck 54 winners past an aggrieved Halep, the third seed who, in the absence of Serena Williams, Victoria Azarenka and Maria Sharapova, was heavily tipped to win the title. The match was in the palm of her hand and it appeared to finally be her breakthrough moment after years of consistent results. Three years ago was something new, so now I know. Jelena recovered from the early loss and played ferociously which saw her win the next two sets comfortably by 6-4, 6-3.
But Halep admitted: "I felt sick in the stomach about playing in this final so maybe I wasn't ready to win it".
"So I think it's kind of maybe a lucky, lucky number or something", Ostapenko told reporters. "I'm just really, really happy".
Halep won the opening set 6-4. So I want to really hit the ball.
But the difference on this day: Halep faded at the end of the second and third sets, while Ostapenko surged, bringing her mother - a tennis instructor who taught young Jelena how to play - to tears in the stands.
Having earned a total of £1m in her professional career before Roland Garros, Ostapenko, who turned 20 on Thursday, will take home £1.65m for Saturday's victory. Accenting shots with high-pitched exhales, she likes points quick and is not shy about unleashing a forehand measured as being faster than that of men's No. 1 Andy Murray.
"When she was 10 years old we came to Roland Garros, ' said Jakovleva".
That, though, is the way the Latvian livewire goes about her business.