Smith is well aware no further slip-ups are permitted as they now lie seven points off Celtic at the top of the SPL.
"Any points that we drop are a blow to us," said the Rangers boss.
"It certainly means that in the three Old Firm games that are left this season, the pressure is heaped firmly onto ourselves.
"But we deserve that because normally we handle set plays very well and we didn't do so today.
"Normally, we defend very well and we gave two bad goals away to Dundee United recently and those little bits of inconsistency have plagued us in games."
Asked whether their remaining fixtures were all now must-win games, Smith added: "We have to win all our games anyway - it doesn't matter whether it is 'must-win' or whatever.
"Today was typical. We were away from home and, territorially, had the vast majority of the game.
"We can only look at ourselves when we don't manage to create any real clear-cut opportunities in that time."