08/09/2015 9:13 AM AEST | Updated 15/07/2016 12:51 PM AEST

Sam Stosur - Frustration Is Thy Name

Elsa via Getty Images
NEW YORK, NY - SEPTEMBER 07: Samantha Stosur reacts after loosing to Flavia Pennetta of Italy during their Women's Singles Fourth Round match on Day Eight of the 2015 US Open at the USTA Billie Jean King National Tennis Center on September 7, 2015 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Elsa/Getty Images)

Samantha Stosur, it has to be said, is the personification of frustration!

She is the consummate professional, a wonderful role model and ambassador for her sport and is regarded with affection by Australian fans -- but simultaneously elicits a degree of despair.

Stosur’s run of good form has ended with a loss to long-time nemesis Flavia Pennetta in the fourth round of the US Tennis Open.

She has previously won this title -- the fourth in the major Grand Slam tournaments – so it’s not like this is a mountain she has yet to conquer.

But more often than not, certainly in recent times, she has failed to make it through the fourth round of a major tournament.

Australians will have been keenly watching this morning, as the match started at a reasonable hour in Australia, but it was all over too quickly, in straight sets.

In fairness, Flavia Pennetta’s record at Flushing Meadow is impressive -- this is the sixth time in the last seven years that she has made it into the quarter finals of this event and she has never lost to Stosur.

Those stats alone should have prepared Australian fans for what was to come, but Sam’s supporters are ever the optimists!

Unfortunately, Stosur can be her own worst enemy and aside from Pennetta playing a well-executed game plan, Stosur racked up 35 unforced errors in the 20 games of tennis it took the Italian to secure her quarter final berth.

Unforced errors are self-explanatory: they are errors in play that are avoidable and therefore unnecessary points lost - 35 of them equates to almost nine games. And nine games in a ‘best of three sets’ match is huge, especially when your opponent only reels off 13 of those errors.

There was, no doubt, much groaning at TV sets in living rooms across Australia as the match progressed and as that familiar sense of frustration seeped into the equation. But there is also no doubt that Samantha Stosur felt the same frustration to her core as another title opportunity slipped away.