Of the starting XI, Krul, Santon, MYM, Colo, Williamson, Tiote, Gouffran didn't play any minutes since the last league game 2 weeks ago.
Sissoko (29 mins), Cabaye (90), Remy (61), Shola (63) weren't exactly bursting their guts over 2 international matches.
How can tiredness be used as an excuse?
It's tactical more than anything else. If you get your players to adopt a no-more-goals attitude they are obviously going to be mentally shot well before the final whistle.