MONTRÉAL, Canada - No.3 seed Elina Svitolina's Rogers Cup title defense remains alive, although her victory over Mihaela Buzarnescu today was bittersweet: deep in an enthralling decider, the Romanian went over on her ankle and was forced to retire trailing 6-3, 6-7(5), 4-3, wiping away tears as she left court in a wheelchair.

It was a heartbreaking conclusion to a match that had been full of dramatic plot twists - particularly for a player who, having lost so many years of her career to injury, had been enjoying a meteoric rise after finally enjoying a sustained period of health.

Two of the many milestones Buzarnescu has hit over the past 12 months came courtesy of her two previous wins over Svitolina: a 6-3, 7-5 triumph at Roland Garros was her maiden Top 10 win at a Slam, and put her into the second week of a major for the first time; a month later, a 6-3, 6-2 win in Birmingham sealed Buzarnescu's first ever Premier semifinal.

But - having scored yet another milestone last week, lifting her first trophy in San José - the 30-year-old had admitted to feeling tired and jetlagged after her first-round win over Qiang Wang here. Certainly, her usual stylish accuracy was lacking. Buzarnescu's game is based around her ability to open up the court with finely cut angles and raking groundstrokes that graze the sidelines; today, shot after shot drifted wide or long.

For Svitolina's part, the 23-year-old showed no discomfort at facing an opponent she had never previously taken a set from. The defending champion's game was absolutely watertight, conceding a miserly two unforced errors in the first set and only ten overall.

Moreover, the three-time major quarterfinalist's serve was on song. Maintaining a first serve percentage of 69% and sending down six aces, Svitolina was able to mostly keep Buzarnescu at bay on return.

In the first set, the Hobart and Prague finalist showed intermittent flashes of the kind of play that had led her to those previous wins - a flurry of glorious winners off both wings and at net led to a love break in the fifth game of the first set - but was unable to sustain it. In the second set, though, she began to cut down on her errors and play with a great deal more freedom.

But when Buzarnescu was unable to convert two break points in the sixth game and - as is so often the case - was immediately broken herself in the very next game, it looked like it wasn't enough. However, the World No.20 simply lifted her game even more, playing inspired tennis to force a tiebreak.

Svitolina, whose razor-sharp grasp of match momentum has been a hallmark of her success, had sensed the potential turning point and also raised her own level, upping the pace and finding some brilliant angled winners, particularly on the backhand side. The Brisbane, Dubai and Rome champion dominated the start of the tiebreak with some of her best tennis of the day, leaping out to a 5-2 lead thanks to some excellent net play.

Buzarnescu was not to be counted out, though. Out of nowhere, the tour's sole PhD holder conjured up five electrifying points in a row, hammering winners down both lines with abandon - and suddenly, she had effected a Houdini-like escape from the jaws of victory. That form carried over into the deciding set, too: the court was Buzarnescu's canvas and the variation and accuracy of her groundstrokes were the tools with which she created a 3-0, double break lead.

Now, it was Svitolina's turn to find some never-say-die attitude. A careless double fault conceded one of the breaks in the fourth game, and that was all the opening the Australian Open quarterfinalist needed to wedge her foot back in the match. A scorching backhand return winner reeled the second break back in.

With the score on serve and the stage set for a compelling climax, it was hugely unfortunate for the match to end in the way it did: trailing 15-30 on her serve, Buzarnescu went over on her ankle while chasing down a Svitolina forehand, and it was clear from her distress that the injury was serious. After medical treatment, the Romanian was wheeled off court, her winning streak and the best form of her life cut short in a horribly sad way.