Let’s look back to last year’s US Open men’s quarterfinals.  Rafael Nadal beat Mardy Fish.  Andy Murray beat Juan Martin del Potro.  Novak Djokovic beat Andy Roddick.  Roger Federer beat Gilles Muller.

Of the eight quaterfinalists, one was very surprising (Gilles Muller), two were surprising (del Potro and Fish), and one was mildly surprising (Roddick).  Let’s see why.  First Mueller. Muller was a qualifier.  The guy played well as a junior, but otherwise is not that well known.

Although del Potro has proved himself a top player, at the time, he had just beaten Andy Roddick and wasn’t even ranked high enough to represent Argentina in the Olympics.  He had a great streak of four consecutive tournament wins, but they were pretty small tournaments depleted of talent because of the Olympics.  The US Open was a kind of coming out party for del Potro.

Mardy Fish had a pretty good year in 2008, but it was a little surprising that he beat his buddy James Blake, though in hindsight, Blake was beginning to slide in 2008 and continues to do poorly (by his standards) in 2009.  Fish is a good, hard-hitting player, a top 20 talent, but not someone you would have picked to be in the final 8.

In 2008, Roddick had been having a down year. He had started the year well, but got injured in Rome, skipped the French, wasn’t really ready for Wimbledon, and decided that he would be better served skipping the Olympics and playing the US Open Series.

In Los Angeles, Roddick got to the final, but he lost to del Potro.  At the time, this seemed like a huge upset.  If he were to have known that del Potro would beat him twice more in 2009 or push Federer to the brink at the French Open, he might have thought it wasn’t such an upset.  What was an upset was his loss to Viktor Troicki at Legg Mason.

Suddenly, Roddick was feeling a bit desperate.  He had been coached by his brother, John Roddick, up to that point, and asked Davis Cup coach, Patrick McEnroe to coach him through the US Open.  It didn’t look good.  He had an early match against Ernests Gulbis, a talented player that everyone thought was on the rise (a year later, not so much), but beat him, and beat Seppi and Gonzalez in the next two rounds rather handily.  No one would have expected that he would have done as well as he did, even if he was capable.

Pretty much, everyone else was expected to be there: Federer, Nadal, Djokovic had been good until the later rounds.  Andy Murray was just starting to climb up the ranks.  He had a respectable Wimbledon (lost in the quarters to Nadal) and won Cincinnati.

Why the history?  Any time you pick dark horses, there’s going to be one or two players that you won’t have anticipated getting that far.  Muller is a prime example.  No one will pick him this year either.

With that in mind, we’ll look at a few dark horses that probably won’t win the US Open, but might make it through a few rounds.  They might also lose early too, so who knows.

John Isner. We only put him first because Isner’s website reference an earlier article.  However, Isner has had a decently good summer.  He reached the semifinals of Indianapolis, the quarterfinals of Los Angeles, and the semifinals of Washington DC.  For a guy ranked around 150 at the start of the year, this is a tremendous accomplishment (he’s currently 55).  Along the way, he beat Berdych, Tsonga, and Haas.  Isner decided to skip New Haven.  Isner needs a pretty favorable draw.  He won’t be ranked high enough to get seeded, but he won’t have to qualify either (he’d probably get a wildcard if he did).  Could upset a low seed.

Sam Querrey. Isner’s summer is pretty notable given how low his rank is, but Querrey’s summer has been stellar.  He hasn’t had the summer that del Potro had last year, which was even better.  Querrey reached the finals at Newport and Indianapolis before finally winning a title at Los Angeles.  Although most of his wins have been against lesser players, he did notch two big wins: Tommy Haas (in Los Angeles) and Andy Roddick (in Cincinnati). Querrey has been committed to playing the entire US Open Series and has done that and even played Newport.  Basically, he’s played every week since Wimbledon.  He’s likely to win the point race in the US Open Series because of this.  The downside?  Will he be too fatigued by the US Open?  Unlike Nadal, Querrey at least doesn’t make the later rounds of most tournaments, except early on, he did.

Jo-Wilfried Tsonga. It’s kinda hard to call the 7th ranked player in the world a dark horse, and to be honest, his record has been very spotty this summer.  He lost to Isner, Guccione, and Murray.  Tsonga has shown this year that big servers give him problem, of the tall variety.  He lost to Karlovic at Wimbledon, to Isner at Washington, and Guccione at Cincinnati.  But, he beat the one guy that really matters, Roger Federer.  Tsonga is so up-and-down, it’s hard to say how he’ll do at the Open.

Nikolay Davydenko. It’s hard to call the 8th ranked player in the world a dark horse, too.  Davydenko has had a pretty good summer.  Too bad it’s on clay.  He won Hamburg and Umag.  He reached the quarters of Montreal where he lost to Andy Murray, and lost to Gilles Simon in Cincinatti in the 3rd round.  He’s upped his ranking the last few months, and can play well on any surface that isn’t grass.  Here’s a guy that could make it a few rounds at the Open.

Lleyton Hewitt. Hewitt is kind of today’s Jimmy Connors.  He’s tough and relishes the battle.  He had a great Wimbledon, nearly knocking out Andy Roddick.  He lost to del Potro in DC and to Federer in Cincinnati.  The key for him is health.  Hewitt’s knee had been bothering him, but presuming he gets enough rest between now and the Open, he might have a few surprises.

Juan Carlos Ferrero. Ferrero, like Hewitt, has been trying to get his ranking respectable.  Like Davydenko, he played on clay after Wimbledon (where he reached the quarters).  Lost to Haas in DC.  Lost to Murray in Montreal.  He and Hewitt are the old men, both former number 1 players, that might create noise.

Tommy Haas. Although hard courts may be Haas’s best surface, he had a very good French Open and Wimbledon.  The hard courts haven’t been so kind this year.  He lost to Gonzalez twice, once in DC, and retired in Montreal.  He lost to Querrey in Los Angeles and Isner in Cincinnati.  The likelihood is Haas is not quite ready for the Open given his record so far.

Fernando Gonzalez. Gonzo got to the semifinals at DC (losing to del Potro) and the 3rd round of Montreal (losing to Davydenko) and retired against Berdych. He’s trending a bit in the wrong direction.  He’s always dangerous.

There are a few other names that haven’t done that well this summer that you might have expected.  Verdasco is perhaps tops.  With his stellar Australian Open performance, you would have thought he’d carry on his success, yet he’s been pretty quiet.  Soderling withdrew from DC and lost to Hewitt in a close match in Cincinnati.

There’s likely to be someone a little unexpected making it far, but the US Open tends to hold to form with most players making the quarterfinals coming out of the top 32 seeds.  Perhaps someone like Safin (ha) can have one last hurrah, but the 2008 Wimbledon was likely his last hurrah.

Although the winner is likely to come from the top 4 players in the world, players like John Isner can hope to make a decent run.