Steven Gerrard refused to point the finger of blame at Kemar Roofe for the late lapse that allowed St Johnstone to snatch a point in Perth.
Gers looked to be on course for a narrow win after Scott Wright had fired his first goal for the club.
But with just seconds remaining, Roofe tried to replicate his wondergoal against Standard Liege earlier this season as he took aim from the half-way line.
The ball was never troubling Zander Clark's goal and the Saints keeper was able to launch one last attack, which led to the hosts winning a penalty.
Liam Craig rammed home as he handed Callum Davidson's team a boost ahead of Sunday's rematch in the Scottish Cup quarter-finals along with a valuable point which trims Livingston's lead in the race for a potential European slot back to three points.
Gerrard – whose newly-crowned champions now stand just three games away from an invincible league campaign – said: "Look, as a team we are 1-0 up and you have got to make better decisions, decisions for the team rather than yourself.
"But he has tried that before and scored from the halfway line so who am I to tell him?
"But as a group, we have been really good this season with our game management and parking our ego up in the final moments of the game.
"Unfortunately tonight we paid for it. It was a penalty, we should have won the header and it was a combination of small errors. But I think over the course of the 90 minutes St Johnstone deserved that little bit of luck."
There was an end-of-season feel to Rangers' first-half display as they rode their luck on a number of occasions.
But Wright opened his Gers account with a sublime finish after being played in by Steven Davis on 55 minutes.
Gerrard added: "I think since Scott has come in, everything we have asked of him he has done really well.
"He is really professional, we are working hard with him on and off the pitch. He is up to speed, he looks ready now to contribute and it was a really tidy finish.
"I thought again he showed some flashes but again there are things he can work on, but so can a lot of other people on tonight's performance. We are really pleased with Scott."
There was controversy just moments after the former Aberdeen winger's goal, however, as referee Euan Anderson handed the hosts a penalty for a Borna Barisic tug on Shaun Rooney – only to reverse the call after consulting with his assistant Frank Connor.
However, Saints did get their spot-kick in the third minute of injury time as Roofe's decision to go for glory backfired, with Jack Simpson penalised for a barge on Chris Kane.
Saints boss Davidson said: "I'm delighted, we started the game unbelievably well and caught Rangers cold a little bit.
"The only disappointing thing was we didn't score a goal or two. Some of the chances were very good.
"Once we lost the goal we didn't give up, we kept going and got our rewards in the end.
"It's not often you play against Rangers and have more shots on target than they do, so that shows how well we played.
"We deserved at least a point and I'm really proud of the players."
