Up Against It Meaning

(idiomatic) In a very difficult position.

Example: 2015 June 9, “Women’s World Cup 2015: England beaten by France in Group F opener”[1], The Guardian (London):
  Yet as intelligently as Rafferty, back at left-back following her recovery from a third ruptured cruciate ligament, was defending against the dangerous Élodie Thomis her side were up against it.