If you were told that Andy Roddick and Andy Murray were playing today, and one lost, which might you pick?  Of course, the answer would depend on who they were playing, but minus that information, you might say Andy Murray, since he’s ranked higher than Andy Roddick.

OK, so let’s look at the opponents.  Andy Roddick played Tommy Robredo.  Robredo just beat Marcos Baghdatis who beat Roger Federer.  Makes Robredo look good, right?  Solid one handed backhand.  Except Andy Roddick has never lost to Tommy Robredo.  And they’ve met 10 times.  Maybe Robredo has a hard time picking up Andy’s serve.  Maybe Andy is actually pretty steady off the ground compared to Robredo.  Maybe it’s in Robredo’s head.

In any case, Andy racked up win number 11 with a 6-3, 7-5 win.

Andy Murray was scheduled to play Robin Soderling.  In a way, this had trouble written all over it.  Murray tends to struggle against big hitters.  He’s lost to Juan Martin del Potro, Marin Cilic, Fernando Verdasco, Fernando Gonzalez, and of course, Roger Federer and Rafa Nadal.  Murray relies on tremendous footspeed to get to shots and change of pace.  But he has some weaknesses.  At this point, Andy Roddick is the steadier player.  If Murray has to play long rallies, it becomes a liability.  He has a relatively flat trajectory.

Andy Murray has a hard time pulling the trigger to hit big shots.  Rafael Nadal sometimes gets gun shy too, but he has such huge spin that it gets offputting to his opponent, and when Rafa does play well, he is playing aggressive tennis, trying to disrupt his opponent, waiting for a weak shot that he can begin to pounce on.  When Murray tries to go for big shots, a few things happen.  First, they never look too dominating.  And second, more importantly, he begins to miss.

Roger Federer, by contrast, has built his game on aggression.  He is looking for an opportunity to go for a winner.  When is game goes off, as it did against Marcos Baghdatis, he allows his opponents to win more games than they should and even then, the match still ends up being pretty close.

Robin Soderling used to be something of a head case.  He would lose focus, get upset.  If you haven’t heard of Soderling before his huge upset of Nadal in the 2009 French Open, it’s because of that.  But then he teamed up with Magnus Larsson, once a French Open finalist, and sometime boyfriend of one Martina Hingis, and he worked on his mental game, trying to get him to stay in the match, to stay positive, and to keep fighting, even when things weren’t looking good.

Soderling took his French Open win and worked his way into the top 10, most recently moving ahead of Andy Roddick in the rankings.

Soderling has a big serve, a huge forehand, and can really hurt players off the ground.  He’s one of those guys that bothers Nikolay Davydenko, even though Davydenko seems to handle the other top pros well.

Soderling easily took the first set over Andy Murray.  Although the match tightened up in the second, Soderling broke for the lead and was serving for the match when Murray managed to break back.  They headed into a tiebreak and Soderling took the early lead, one he never relinquished.  Soderling has the ability to take a seemingly innocuous rally, and switch directions to hit a winner, which he did against Murray.

With this, Murray exits in the quarterfinals and loses points relative to last year.  He seems to have regressed some, despite making good progress heading into the Australian Open.  Soderling has a 2-0 record over Andy Roddick.  They’ve played close matches on fast surfaces.  Andy Roddick will want to turn this around, but if Soderling beats Roddick, he may solidify his ascendancy to the top.

In the other semifinals, Rafa Nadal, the defending champ, will play Ivan Ljubicic.  Ljubicic will have to come up with some veteran magic to beat Rafa.  I just don’t see it happening.

Of all the semifinalists, only Rafa is the one expected to be there.  Still, Roddick and Soderling are seeded players, ranked in the top 10, so their appearance should be reasonable, especially with Davydenko having to withdraw from the tournament.