Warnock hot-footed across London to join Rangers last March after the Eagles went into administration, and his new side are making short work of the Championship.
But they needed Iceland striker Helguson's dramatic intervention to make it nine wins and a draw from their opening 10 games.
Adel Taarabt put Rangers ahead just after half-time, but Palace looked like they had salvaged a point two minutes from time through substitute Kieron Cadogan.
However, Helguson struck in stoppage time to keep the Hoops six points clear at the top and well on course for a return to the top flight after 15 years.
It could have been so different for the hosts, who almost got off to a dream start when midfielder Owen Garvan crashed a shot against the post in only the fourth minute.
Rangers goalkeeper Paddy Kenny was then called into action to make a fine double save from Wilfried Zaha, before the visitors broke to the other end and Julian Speroni repeated the trick to deny new Scotland recruit Jamie Mackie.
Helguson then met Hogan Ephraim's corner but his header flew wide.
Kaspars Gorkss came even closer when he deflected Helguson's drilled ball across goal onto the crossbar.
Palace continued to threaten as well with Clint Hill, who followed Warnock to Rangers, bravely blocking Andy Dorman's shot and from the corner Ephraim clearing Julian Bennett's header off the line.
But Rangers went ahead three minutes after the interval after an elementary mistake from the most experienced man on the field.
Dutch veteran Edgar Davids hit a woefully short backpass to leave Speroni in no man's land and allow Mackie to round the keeper and unselfishly tee up Taarabt for a tap-in.
Helguson could have doubled the lead on the hour mark but headed Taarabt's corner wide.
But Palace kept going and substitute Anthony Gardner twice put headers wide while Zaha and Calvin Andrew also went close.
And they grabbed the leveller when youngsters Zaha and Cadogan combined in style.
Zaha skinned Hill with a superb piece of skill and crossed for Cadogan, who was given his debut by Warnock, to fire past Kenny.
But Rangers were not finished and when substitute Tommy Smith swung in a cross, Helguson challenged Speroni and managed to bundle the ball home to keep Rangers' promotion charge on track.