Ustiugov is an angry and motivated man that's in really good shape right now.  The format suits him pretty well, despite there only being one sprint at this tour.  Had there been another one, Sundby would have been even more on the defensive.  The skiathlon tomorrow should be interesting.  Heavy snowfall, a tough Oberstdorf course (though not as technical as Val Mustair), and 20km's+bonus sprints should make for some exciting racing.  If the snow is really as heavy as they say, then it's going to be hard to break the race open, but you never know with Sundby.  Technically he is very efficient in both styles and if he's feeling really good, he might try to open the gap already during the classic portion.  If the snowfall isn't that much and the tracks aren't soft and beaten up, then we may see some moves coming in early for sure.  Another possibility is that Ustiugov and Sundby may not go that hard.  They have a good advantage over Harvey, Larkov and the others, so they may just focus on getting to the finish line without too many problems.  If the contenders behind the front two want to gain time back, they'll be going for those bonus seconds.  Having said that, people have blown up in these types of races before.  They'll go for the sprints, but then have nothing left later in the race.  Again, my thinking is that the front two may not go all out tomorrow.  They'll focus on the handicap pursuit on Wednesday and will work together to extend whatever lead they have on the rest of the field.  If the gaps are similar by the end of tomorrow, I expect Sundby to catch Ustiugov in the 15km handicap and they'll work together.  If that happens, and they do work very well, then the race really will be between two men.  Krogh lost almost a minute in the 10km yesterday, so he'll need to gain good chunks in every stage.  Harvey will be consistent (as he always seems to be in these tours) but he has had problems in individual distance race starts in tours (like the one in Toblach, the 10km skate later this week) and the Alpe Cermis where he hasn't been able to match the best or simply not started the stage at all.  I don't see him making the podium.  Larkov will be tough as well, but again, the final climb may prove too much.  Toenseth had a poor final climb last year, despite his light frame and good, efficient technique.  That battle for 3-10 will be just as good as the battle for the title.  This may be the year where Sundby is finally beaten in a stage race.  Not counting the 2015 tour title that was stripped from him, he needed the last stage of the Ski Tour Canada to overtake Ustiugov.  I think Ustiugov may be even more tough this year.  The big question is the Alpe Cermis, as it is for virtually everyone.  I personally don't think he'll lose much, if anything, before the final stage.  
The women's race will be another similar battle.  I don't think Oestberg will have enough of a time gap, if any, to hold off Weng, but who knows.  I hope Parmakoski gets closer and then it's a three horse race for the title.  Nilsson needed another sprint race to have a shot at a podium, so I don't think she'll get a podium, but a top 5 or 6 is very probable.  Tomorrow's skiathlon and the Alpe Cermis are the danger stages for her.