Yes, I've found that it doesnt neccessarily improve the skills, per se...to me it seems like they make the right plays or come through in the clutch more often.
I watch alot of the games to see the weakness in my players, and I do notice that in the fourth quarter or when a rally is needed, or a big stop is needed, my team comes really close.
I also make sure my enthusiasm is near 10 at all times if I can...and that enthusiasm plus the experience can really be an edge in the fourth quarter.