Past his prime? Undoubtedly, except he went on to win the US Open less than a month later. Since then Mr Mathieu has very much been the nearly man of French tennis. An undoubted talent, but justifiably seen as way too flaky.
I can't argue with that, but continue to enjoy the guy's intensity (often is own undoing) which I think French tennis could do with a bit more of. He lacks Gasquet's stylishness but is no less the natural shotmaker for it.
That damage he's capable of inflicting may have been part of the reason why he seemed a lot more relaxed - happy even - after managing to pinch a set off Roger Federer today, who seems to be clicking into gear, though you never know these days.
No, you never know. Do you Novak? Yes you, 2nd best clay courter in the world. Made-the-semis-at-RG-these-past-three-years-only-to-be-dumped-out-in-the-third-round-by-a-tier-two-player Novak.
That's pretty harsh actually, as the guy he went out to happens to be one of my favourite players, a real Custodian of the single handed backhand.
Which brings me to the question of why Phillip Kohlschreiber has not made a breakthrough these past few years. You see, both Mathieu and him have been filed under 'Coulda Been a Contender' within Tennis Is Served's dusty archives for some years now. The third guy there is Andreas Seppi.
The common feature with these three, that arguably sit at the top of a great mountain of players known as the 2nd tier, is that every so often you can depend on them to come out of (not quite) nowhere, and play a match (sometimes at the expense of a top tenner) that leaves you wondering why they've never been a top ten player.
Andreas (highest ranking #27) did it against Safin last year at Wimbledon - still my 2nd best match of that event.
Mathieu (highest ranking #12) , besides that big win against Sampras, played one of the best clay court matches we've had in recent years when he lost to Nadal at RG in 2006, in an encounter lasting nearly 5 hours.
And as to Kohlschreiber (highest ranking #22), well you probably remember him taking out the A-Rod at Melbourne last year. And then you had today.
Yet for all these wondrous exploits, there they are, languishing away year after year as top 40 players.
And in Phillip's case, I've never been able to figure out what, if anything is holding him back. Apart from that obscene hip swivelling motion he goes through when serving, which should be subject to some sort of censorship. 'The following second serve has been rated 15, and features hip-swivelling from the outset, that some viewers may find offensive'.
I first saw him in person at Wimbledon in 2006, playing on an outside court against a Columbian player whose name I can't remember. Admired the backhand even then, but off I went puffed up with my own importance, a ticketholder of a well placed seat on court number 1 where I'd get to see Agassi, Venus and Hewitt.
He plays Tommy Robredo next, a match I expect him to win. But there I suspect this run, like many before it will come to an end. Or will it?
See, if he wins that he plays one of Tsonga or Del-Potro. Great run both these guys have been having but neither of them the most natural clay courter. And then who? Roddick? Monfils? Haas? Federer?
That part of the draw suddenly got very interesting. Though not as interesting as the question of whether we'll see 'The Pink Pounder' deliver a bagel to Soderling tomorrow. I'll be satisfied with a well-timed stink-eye. Not convinced any Babolat-embossed hatchets have been buried just yet.
Quick hits on the womens side.
Elena Dementieva went out to Sam Stosur and in one of the more bizarre quotes I've heard this year, cited 'physical conditioning' as the reason for not producing her best tennis. That's about as believable coming from someone as supremely fit as her as it is from David Ferrer.
That means that there's now only three ladies standing in my list of RG picks for this year. The remaining three being Dinara, Svetlana and Jelena. Not too concerned just yet, with the straight sets wins these girls have had.
Serena Williams eventually came through a three set match marred by an incident in the first set that saw Maria Jose Martinez Sanchez hit by a ball Serena drilled her way. That 'return' sailed past Serena and the point was awarded to Maria, despite Serena's protestations that the ball came off her body. Maria kept schtum. Make of that what you will - I only saw one replay that wasn't too clear.
Lastly, Wozniacki's stay at RG came to end today in a straight set defeat to the Romanian Sorana Cirstea. The story here of course was the back injury that caused Caroline to call an injury timeout just two points away from defeat. But I want instead to call attention to the firepower of the young Romanian who was matching (and sometimes outhitting) Caroline shot for shot. It's as unimaginative as ever, but is I'm pretty sure, amongst some of the most accurate hitting on tour today. Some of the rallies these two were having were preposterous. Not surprised Caroline's back gave way. Keep an eye on that one.