The Ibrox club are lacking striker potions for their SPL clash against Hearts tomorrow, with Kris Boyd, Kenny Miller and Steven Naismith all ruled out and Nacho Novo and Kyle Lafferty doubtful.
Rangers stretched their SPL lead last weekend after Novo's late goal earned them three points at New Douglas Park against a Hamilton side who dominated the first half. Smith's side also needed 210 minutes to see off the Accies in the Active Nation Scottish Cup, so the Ibrox manager knows his team cannot afford to be complacent as they look to retain their advantage over Celtic, who have a game in hand at Kilmarnock.
Smith told Rangers News: "Against Hamilton on Saturday, we were fortunate to come out on top and that shows us how tough it's going to be. When you look at our squad and what we've still got to do, we might well need that gap we have just now if things are going to go in our favour in the championship.
"We are the ones under pressure. That's always the case when you're trying to achieve good results. Going into Saturday's game there, we didn't have enough substitutes to fill the bench and that brings problems. We still have a situation where the suspension of certain players could kick in and that could have a major effect.
"We've run at an average of four injuries since the start of the season so we're by no means home and dry and there's a lot to lose.
"The gap we have to our advantage isn't something that we can allow to lead to complacency. We just need to keep working hard and striving for positive results."
Rangers let slip a seven-point lead two seasons ago – when their run to the Uefa Cup final stretched their squad – and overturned the same gap last season to reclaim the title.
Smith knows the remaining two Old Firm derbies will have a huge bearing on the destiny of this year's championship.
"People are saying there's a nine-point difference but I never look at it that way," Smith added.
"Any club with an opportunity to get that gap down would be expected to reduce it.
"What we have done is created a genuine six-point gap and at this stage of the season, it's a far better situation than we were in last year. But the pressure is on us to once again show the same consistency we displayed towards the end of last term.
"We have to look at that more than anything else. Points gaps just now don't matter, it's what we do going forward that counts.
"Celtic had a seven-point advantage around this stage a year ago and with a good level of consistency, we cut that back. The gap we have now certainly isn't a big one."