Top 5 Upsets of 2017 (No.1): Ostapenko's Roland Garros stunner vs. Halep

After counting down the Top 5 WTA matches and Top 5 Grand Slam matches of 2017, our year-end review moves to the biggest upsets of the season. No.1 on the countdown is perhaps the biggest upset ever, as unseeded Jelena Ostapenko came of age at Roland Garros, stunning Simona Halep for her first Grand Slam title.

WHAT HAPPENED: It was a classic “David vs. Goliath,” only if David traded his slingshot for a machine gun.

Born on the same day Gustavo Kuerten won his improbable first French open title, Jelena Ostapenko was truly firing bullets throughout the fortnight, striking 245 winners to barrel past the likes of Samantha Stosur, Caroline Wozniacki, and Timea Bacsinszky en route to the biggest final of her career. Though the Latvian lacked experience - having never been ranked inside the Top 30 before Paris - she kicked off the clay court season with an expert in Anabel Medina Garrigues. Along with a new coach, she also has swagger for days, never doubting her high-octane game and showing dogged determination to dismantle the defenses of the veterans she faced.

Simona Halep was supposed to end Ostapenko’s excellent adventure. A combination of the trio that came before her, the No.2 seed had Bacsinszky’s clay court comfort, Wozniacki’s relentless defense, and some of Stosur’s aggressive abilities.

Simona Halep was supposed to end Ostapenko’s excellent adventure. A combination of the trio that came before her, the No.2 seed had Bacsinszky’s clay court comfort, Wozniacki’s relentless defense, and some of Stosur’s aggressive abilities, all of which she had used to reach her first Grand Slam final since 2014, when she narrowly lost to Maria Sharapova at this very tournament.

A win would conclude the Spring of Simona, one that saw her reach the semifinals of the Porsche Tennis Grand Prix, the final of the Internazionali BNL d’Italia, and win her third Premier Mandatory title at the Mutua Madrid Open - on the highest possible note. It would resolve Halep’s career arc in one fell swoop, not only earning her a maiden major title, but also the No.1 ranking.

The Romanian had already eliminated Karolina Pliskova from the last for the latter in a thrilling three-setter in the semifinal, and after physical and emotional struggles stunted the opening salvo of her season, Halep was never in a better position to grab what had so often eluded her.

Enter Ostapenko.

From the first game, it was clear Halep would hardly have the match her own way as the 20-year-old blasted return winners to secure an opening break.

Read more: Ostapenko shocks Halep for first Grand Slam title

Halep broke right back and began mixing up the pace as the first set came to a close, upsetting Ostapenko’s rhythm and drawing just enough errors to put herself six games from the title.

Riding that momentum into the second set, Halep reduced the distance to a mere nine points, earning three break points on the Ostapenko serve, the conversion of which would have given her a 4-0 lead.

Halep couldn’t find her happy medium on any of the opportunities, too passive on some and too aggressive on another, gunning a backhand that narrowly missed the line.

Ostapenko ultimately held and used the lifeline to dig out of the disappointment that featured heavily through the start of the second, promptly winning six of the next seven games - not to mention the hearts of the Court Philippe Chatrier crowd - to level the match.

The decider followed a similar script. Halep got within three games of victory only for Ostapenko to roar back in her now-signature style, striking her 54th winner of the match on championship point - a searing backhand return to seal her first Grand Slam title, 4-6, 6-4, 6-3, in an almost two hour epic.

Read more: Top 5 Upsets of 2017
No.5: Osaka vs. Kerber, US Open
No.4: Bellis vs. Radwanska, Dubai Duty Free Championships
No.3: Krunic vs. Konta, US Open
No.2: Lucic-Baroni vs. Pliskova, Australian Open

WHAT THEY SAID: Anyone looking for Ostapenko to wax poetic on her career breakthrough were unaware of the fact that the youngster plays as quickly in the pressroom as she does on the court, politely answering each question as directly as possible.

"I always had the possibility I could hit the ball really hard. So that's why probably -- and if I have a chance to go for a shot, I'm trying, and it's quite helpful," she said in what had to be the understatement of the year.

"I'm really happy, but I still have to improve some things and to get better as player. And so I will work hard to climb the ranking and to maybe win some more titles."

Halep was understandably more emotional in press, likely still stunned at the sudden reversals in each of the second and third sets.

"She played really well, all the credit. She was hitting very strong. At some point I was like a spectator on court. She deserved to win.

"It's tough. It's a tough moment for me, but it's gonna go away, I hope, with the time."

WHAT IT MEANS: Neither Halep nor Ostapenko went away as the season turned back to faster surfaces, each reaching the last eight at Wimbledon and finding themselves back on court together playing the China Open semifinal.

In a full circle moment for Halep, the Romanian conquered Ostapenko in straight sets to - at long last - clinch the No.1 ranking, holding on to the top spot through season's end.

Thought to be erratic at best, Ostapenko displayed remarkable consistency following her French Open triumph, winning a second title - and first on the WTA level - in Seoul, making back-to-back semifinals in Wuhan and Beijing to assure herself a BNP Paribas WTA Finals Singapore presented by SC Global debut.