Managers are judged on all competitions.
Moyes 42%...Martinez 43%.
OK, I can see where you are going with this, using his win percentage rate as a debating point which in your eyes does not make him out as bad as many make out.
But when you strip that back and look a little deeper, and realise
a) he inherited a much better side and a consistent top 7 team which Moyes had left him which was dramatically improved from the one Moyes took over.
b) year by year in the 2 that followed his good first season it is hard not to see with your own eyes that he took that team and destroyed it with his clueless ideas of defending and emphasis on tepid, toothless and pointless over egging of possession.
c) Most of his signings were awful bar a small handful (Lukaku, Barry, McCarthy being his saving graces, with Besic a hard one to call due to injuries)
d) At the end of the day, he won zero, same as Moyes and only qualified for Europe 1 season in 3.
So all in all, he was a bit of a disaster once he had ruined the side he inherited and had undone all of the work his predecessor had done in establishing us as a top of the table side again, after years in the bottom half of the table prior to his arrival.
I could go on, but it's probably pointless, I am not going to change your mind and you nor mine. The man was a complete disaster after his first season IMO, no cup runs are going to gloss over that, any half decent side can have a cup run with the right draw.
Oh and by the way, I was all for his appointment as I thought he seemed like he deserved a chance. In hindsight the cup run somehow managed to gloss over his relegation for some reason, don't think I thought that one through at the time!