P.S Congratulations for your bloging activities, krystlel, great work and analysis as usual.
I think it is safe to say that David won't be playing the doubles in the final. Different circumstances this time. Most players would have trouble playing three consecutive days when they have to face both Nadal and Ferrer in the singles, let alone David. The second, being that Verdasco/Lopez are a good doubles team and it's not worth it because they wouldn't be favoured to win it anyway.
Personally for me, I thought it was not necessarily a bad decision, but it didn't work out in the end. Had he not played the doubles and lost to Davydenko, then maybe people would be thinking he should have played the doubles. They were close to losing in straight sets, and they were close to winning, both which would have been favourable outcomes. It was a decent gamble because it would have been fine if they had won easily, won in a long match or lost quickly, only a long match that resulted in a loss would have been bad. The Kunitsyn/Tursunov doubles combination didn't look so strong on paper and David hadn't lost a doubles (or singles) match at home before. Maybe they could have just played better towards the end of the fifth set in the doubles. Or maybe they could have taken out Canas instead. Too many variables.
By the way, I thought Canas was exceptionally poor in the first two sets but David didn't play that well either. Given how many times the pair of them got broken, maybe they could have gone with someone with a big serve, like Calleri. His passing shots would have been more effective also, given Canas' groundstrokes looked weak.
So David didn't win his last two matches, but there were many positives to take. They're in the finals, playing at home and this will be the biggest occasion in his career (from his point of view). In fact, it must be exciting for all tennis fans in Argentina. How awesome would it be if they played the final in Cordoba? I'm excited already. I was most pleased that he was able to prove that he can still elevate his level in Davis Cup, and of course it was good to see him all fired up.
I agree with Krystlel's match analysis (when Davydenko was server for 3rd set we tryed to desconcentrated him shhhhhh).