MOSCOW, Russia – Ons Jabeur scored arguably the biggest victory of her career at the VTB Kremlin Cup as she ousted WTA World No.8 Sloane Stephens, 6-3, 6-2.

With just eight Top 50 career wins to her name before meeting the No.3 seed, was seeking to make her first quarterfinal at a Premier event. 

Against an out-of-sorts opponent, she made a dream start, breaking in Stephens’ opening service game and seeing the set out comfortably, 6-3. The second set followed a similar pattern, with the Tunisian getting into the driving seat early and refusing to give it up as her opponent failed to find any measure of control.

"I'm really happy, especially after all the matches I've played here. Hopefully, I can continue playing this way," she said after the victory.

The match started somewhat inauspiciously for the Tunisian, who was forced to save break point in her opening service game, yet this proved a rare crisis moment in what was a comfortable first set, punctuated by errors from Stephens, who played in an uncharacteristically lacklustre manner.

Although the American fashioned chances, she was unable to profit from her good work, often allowing the ball to leak out of court when she would habitually have struck a winner. By the end of the opening set, she had made just four winners in comparison to 15 unforced errors.

Jabeur, meanwhile, focused impressively after dropping serve in the third game to come back and claim the opener. Even a brief appearance of a cat on court, which drew a puzzled stare from the American, did not see her lose concentration.

At the beginning of the second set, there was little response from the 2017 US Open champion. At 30-15 up in her opening service game, she would have expected to take the initiative, but instead lost three points in succession, making the type of errors that cost her the opener.

Jabeur raced through the subsequent service game, winning it to love and punctuating it with a powerful ace, which was just her second of the match.

In the seventh game, she took full control as she earned a double break. The WTA World No.101 had a tendency to overuse the dropshot but played some glorious short balls, too. One particularly fine example helped her manufacture a couple of break points, which she needed only one opportunity to take, sending a forehand down the line into the open court to establish a 5-2 lead.

And Stephens’ tough day would soon be over, as she fired wide on Jabeur’s second match point.

Anett Kontaveit, who ousted Kristina Mladenovic, is up next for Jabeur, who played down some lower back pain she seemed to suffer from in the second set.

"I'm going to speak to my physio, but hopefully it's nothing serious and that some stretching will help me be ready for the next match," she said ahead of a meeting against the No.8 seed.