I just did the last "challenge" I did on TE2013, back in April ( => topic15-27740.php
I beat the same player with the same settings 6/1 with a double break again, on 1st try instead of the 2nd, so I guess there's no fundamental change.
However, as I did that set at 120hz, after, just to be sure, I tried at 60hz : I got beaten 6/3. I did less aces & the guy was on fire.
Now, if I didn't know the guts of the game, I'd probably say something is wrong with it, but actually, I just played less focused, got a bit unlucky and the winning spirit wasn't on my side...
Anyway, there's a small change in how you see the ball. I'd recommend you to try to set your monitor refresh rate to 75hz (I checked and it seems it's your monitor max refresh rate), maybe it'd help you. At very least, it should look more smooth and thus less tiring on the eyes if you play a long time...