A tournament generally turns a corner when it reaches the round of 16, at which time the atmosphere intensifies as players eye the final weekend with the intensity displayed by Ivanovic above.  While the women rounded that bend yesterday, the men reach the intersection today.  Who has their eyes on the prize?  Tuesday preview straight ahead:ATP:Federer (1) vs. Berdych (16):  Since his stunning upset six years ago in Athens, Berdych hasn't duplicated his initial success against the world #1.  He took a two-set lead in Australia last year, only to donate crucial points as Federer mounted a comeback.  Although he easily could find himself in a winning position again, considering Federer's mediocre form here, it's likely that one of the ATP's greatest underachievers still will find a way to lose.  Pick:  Berdych.Verdasco (10) vs. Cilic (7):  Before the tournament began, I picked Verdasco to pull off the mini-upset here.  After watching him wallow through a hideous match against Melzer (in which he committed a dozen double faults), however, I was struck by the contrast with the crisp, efficient manner of Cillic when he defused the dangerous Baghdatis.  His calm consistency should allow him to weather the ebbs and flows in the Spaniard's volatile game.  Pick:  Cilic.Fish vs. Youzhny (13):  This match might be the most difficult to call.  There's no question that Youzhny is the better all-round player and more consistent performer.  Yet Fish has been serving brilliantly here and gaining confidence.  Moreover, a long, frustrating three-setter against Wawrinka yesterday may have physically and emotionally drained the Russian.  One senses that the American might have one last win in him here.  Also, I've stored quite a bit of money in the bank over the previous two days, so I can afford a high-risk, high-reward proposition here.  ;) Pick:  Fish.Gonzalez (9) vs. Soderling (5):  Probably the most exciting ATP fourth-round, this encounter should feature inspired shotmaking and ball-bruising groundstrokes.  Whereas Gonzalez looked rusty at times during his three-set victory over Monaco yesterday, Soderling extended his momentum from Indian Wells with a suffocating performance against Petzschner.  Both of his groundstrokes can deliver mighty blows, while the Chilean relies almost exclusively on his forehand to control points; the Swede should seek to expose this asymmetry during rallies.  Pick:  Soderling.Tsonga (8) vs. Ferrero (12):  A stark contrast in personalities, this clash opposes exuberant athleticism and unbridled aggression against crisp technique and meticulous point construction.  Ferrero managed to blunt Isner's serve, but the Frenchman has a far more imposing ground game than the American upon which to buttress his bombs.  Pick:  Tsonga.Ferrer (15) vs. Nadal (4):  In late 2007, Ferrer proved that he can profit from his compatriot's struggles; that year, he defeated Nadal at both the US Open and the year-end championships.  He remains one of the few players who can match Nadal's ball-retrieving skills, and his style will force Rafa to take the initiative, not always a comfortable position for him.  If the fourth seed plays as he did in the first set against Nalbandian, he'll probably lose.  But he's enjoyed considerable success against fellow Spaniards, and I suspect that he'll rise to the occasion.  Pick:  Nadal.Roddick (6) vs. Becker:  I laughed the German off against Robredo and paid for it.  This time, though, I'll have the last laugh.  Pick:  Roddick.Almagro (33) vs. Bellucci (27):  Opportunity knocks for both of these players, neither of whom has needed to defeat a higher-ranked player en route to this stage.  When Bellucci's lefty serve is clicking, he can be hard to break, but Almagro's serve also is imposing at its best.  The Spaniard's greater experience at this level and more balanced groundstroke game (cf. Gonzalez-Soderling) should see him through.  Pick:  Almagro.WTA:Bartoli (13) vs. Wickmayer (12):  Opportunity also knocks in this quarterfinal, which both players reach without having dropped a set.  Can Bartoli's quirky game rattle Wickmayer as it did Kuznetsova?  The Frenchwoman kept her focus yesterday while her opponent lost hers-a formula that often has succeeded for Bartoli-but she'll have to work much harder for a victory tonight.  Far more mentally sturdy than the top-seeded Russian, this new Belgian star of the future is ready to consolidate her US Open run with another marquee semifinal.  Long overshadowed by Azarenka and Wozniacki, she may eventually rival both of them.  Pick:  Wickmayer.Venus (3) vs. Radwanska (6):  They played here last year in the fourth round, when an error-riddled Venus barely eked out a three-set win against the crafty Pole.  Over the next few months, she thrashed Radwanska twice by identical scores of 6-1, 6-2.  The conclusion is clear; Agnieszka will be helplessly overpowered if Venus is firing all of her weapons, but she has a reasonable chance to pull off an upset if the American fails to perform at a high level.  Judging by her match against Hantuchova yesterday, the latter option is more likely. Moreover, the Pole won't open a door for her to escape, as did the Slovakian.  Still, Venus has persevered through inconsistent patches to win all except one of her matches this year, compiling the best record of any WTA player.  One suspects that she'll rein in her rebellious forehand and unleash her most explosive serves when it matters most.  Pick:  Venus.***After a perfect predicting Sunday in the WTA, we enjoyed a perfect predicting Monday in the ATP.  Overall, we accumulated a 14-2 record yesterday (not far from Venus' record in 2010).  During these last two days, in fact, we've been 27-5:  13-3 in the ATP, 14-2 in the WTA.  Let's hope that we continue to maximize the aces and minimize the unforced errors!  :)