"I suppose the upside is we've shown a lot of character to come back and perform really well under pressure and stick to our task and not lose belief," MacDonald said about his team's 33-24 win against the Blues.
"It's pleasing because we're winning the games but we don't what that happening every week. We realise we've probably used up all of our free lives."
Asked whether the Crusaders could look to rest a few players in their next match against the Force at AMI Stadium on Friday, MacDonald said: "Given our performances over the last three weeks I don't think we're in a position to take anybody lightly. We're really searching for an 80-minute performance. That's a priority and we're at home. We had a stunning crowd in [for Blues] and we want to put on a performance that they can be really proud of."
Apart from their turning the fightback from a seemingly impossible position into an art-form, the Crusaders have shown resilience in overcoming injury.
They were without fullback Israel Dagg, who underwent knee surgery today but expects to return in six weeks, wings Seta Tamanivalu (hamstring) and Digby Ioane (hand), and centre Jack Goodhue, who was a late withdrawal from the Blues match due to a calf injury.
Losing first-five Richie Mo'unga to a hand injury after the win over the Brumbies was a serious blow but Mitch Hunt has stepped up and performed with composure in his first season at this level.
"It just means we're not as vulnerable to injuries as some teams who roll the same team can be," MacDonald said. "It gives us depth and confidence - the fact we can beat a New Zealand team with probably seven or eight of our starters out was a real credit to our guys."