The striker, who is on loan from Bolton, missed an open goal just seconds after coming on as a second-half substitute much to the dismay of Portugal legend Sousa.
But defeat would have been harsh on Palace in a game that in fairness no side really deserved to win.
Palace started brightly but Rangers created the first decent chance when striker Daniel Parejo scuffed his ninth minute effort from Patrick Agyemang's low cross.
Eagles midfielder Ben Watson saw his strike from distance fly a foot wide soon after as Palace started to take a grip on proceedings.
But for all their possession, the home side failed to create any real clear-cut chances before Paul Ifill forced a good save from Radek Cerny in the 42nd minute with a crisp half-volley just that the former Spurs keeper turned around the post.
Then came Helguson's embarrassing miss when clear through.
Agyemang squared to the former Watford man but with the whole goal to aim at and keeper Julian Speroni stranded, the Rangers debutant stroked wide.
Shefki Kuqi saw a header from John Oster's cross drop straight to Cerny in the 69th minute as Palace upped the pace, while Sean Scannell sent another header, this time from a Nathanial Clyne cross, wide just a minute later.
QPR keeper Cerny was thanking his lucky stars in injury time after failing to hold onto Craig Beattie's drive from the edge of the box.
But somehow the away side managed to scramble the ball away to spare their keeper's blushes and rubber stamp their point.