Dexter Blackstock climbed off the bench to secure a dramatic victory for QPR against Coca-Cola Championship play-off rivals Preston.

The striker grabbed his 10th goal of the season four minutes from time to maintain Rangers’ promotion bid.

A controversial penalty decision from referee Alan Wiley had earlier looked to have gifted Preston a point.

Rangers were leading 2-1 courtesy of Heidar Helguson’s double, but in the 60th minute Premier League official Wiley adjudged Sean St Ledger was felled in the area by Rangers goalkeeper Radek Cerny.

Callum Davidson gratefully slammed the penalty past Cerny, only for Blackstock to deny the visitors with his late intervention.

On-loan Bolton striker Helguson took his tally to three goals in the last two games in the first half, either side of Chris Sedgwick’s first goal in a year for Preston.

The hosts, who have been in fine form at home this season, almost went ahead inside the opening two minutes only to be denied by a superb double save from Andy Lonergan.

The goalkeeper hurled himself to his right to keep out Lee Cook’s curling shot, and then managed to block the follow-up from former Preston striker Patrick Agyemang.

They took the lead after quarter of an hour when the impressive Cook swung in a cross from the left and Helguson darted in front of St Ledger and headed past Lonergan.

But 12 minutes later Preston hauled themselves level with their first meaningful attack.

Skipper Paul McKenna was given far too much space in the penalty area and he picked out Sedgwick, who planted a firm header past Cerny and into the corner of the net.

The visitors should have gone ahead moments later, but Youl Mawene blasted over the crossbar from close range following a corner.

And Rangers went back into the lead 10 minutes before half-time when Agyemang brought down Martin Rowlands’ corner and Helguson prodded the loose ball over the line.

They almost had a third when Agyemang played in Cook, but the on-loan Fulham midfielder missed his kick in front of goal.

After the break, Lonergan saved well from Cook and Agyemang, while Eddie Nolan skied a good chance for Preston.

But the game exploded in controversy on the hour when Wiley adjudged Cerny to have brought down St Ledger in the area despite not a single Preston player appealing for a foul.

After the protests from the hosts had died down, Davidson stepped up to thump the ball down the centre past the diving Cerny.

Substitute Mikele Leigertwood and Hogan Ephraim fizzed shots wide as Rangers went in search of a winner.

And the breakthrough came when Rowlands swung in a free-kick which Blackstock met with a glancing header to give Lonergan no chance.