This would be a really tough match for Haye because Chagaev has a very strong chin!!! I would make it a 50/50 fight....it certainly wouldn't be a fight I'd bet on. That being said, I still think Haye has got a much better chance of beating Wlad than Chagaev has....just because of his supreme athleticism and KO power.
if haye cant put him down with some bombs then ruslan wins, see stylistically i always liked hayes chances against wlad, but not against the other top heavies.
I always thought that Haye against the likes of Chagaev, Ibragimov or Povetkin would be harder fights for him than either Klit. I still had Haye as the underdog against the Klit's but his best performances in the past have come against big guys who fight at range and he's had problems with the stockier close-in fighters.
I think the key to Haye being victorious in this fight is to box and not go for the KO as he is known to do. If he tries to bomb out Chagaev early, and finds his chin too tough to crack, there's the chance that he could gas out as has happened in the past. His atleticism and hand speed should allow him to take rounds of Ruslan...and as long as he can avoid a big bomb he could get the win.