In terms of how the bookies have positioned the two it seems to be a mismatch with Roddick at 1.30ish and Gonzalez at 3.50+, however i believe that it will be much closer than the bookies have it.. so in terms of betting it would be an upset, as Gonzalez is paying over $3.50 in a two horse race..
I've checked the stats for their past matches in the draw and Roddick has been the more impressive even in his match against Verdasco. I think Roddick will take him - if Blake can bagel Gonzo...Roddick can cause some significant damage.
I've not checked the stats yet, but I'm liking Dent to beat Canas. Canas is suffering with a knee problem and he struggled like anything against Chela. Dent will hold serve more easily...but he is less likely to break. A word of warning - Canas leads 2/0 h2h - all in straight sets. Also, we all know that Canas loves to eat serve & volley players for dinner.