Cotterill got his opportunity just before half-time but saw his spot-kick saved by Paddy Kenny as the teams shared the spoils in a dull encounter.
Just three places separated the sides going into the clash and it showed as both enjoyed their share of possession, while failing to get an all-important breakthrough.
The Swans, clearly brimming with confidence having lost just once in their last six, showed plenty of endeavour in the opening stages as their free-flowing approach caused the visitors problems.
But it was QPR who manufactured the first opening as Hogan Ephraim’s clever ball found Jamie Mackie, who fired into the side netting.
That proved the catalyst for a wave of possession for Neil Warnock’s men, with Heidar Helguson looking particularly threatening.
The former Fulham striker nearly put the leaders ahead midway through the first period, but Dorus De Vries was on hand to parry his fizzing effort away.
Alejandro Faurlin, back in the starting line-up for the first time since returning from a hamstring injury,
was also enjoying some fruitful moments, although his final ball often left a lot to be desired.
Brendan Rodgers’ side reminded the visitors of their quality in the 31st minute, though, as Stephen Dobbie forced a smart save from Kenny.
They should have taken the lead moments later but, after Mackie was harshly adjudged to have brought down Darren Pratley, Cotterill missed from the spot.
The hosts were nearly made to pay for their miss two minutes later, but Shaun Derry’s goalbound 25-yard volley was blocked by Garry Monk.
The referee’s poor display was continuing to infuriate the fans, although Swansea were lucky not to be down to 10 men when Alan Tate, who was already on a yellow card, elbowed Adel Taarabt.
Clearly rattled by the hosts’ riposte before the break, QPR came out strongly after the interval with Mackie forcing an excellent save from De Vries.
Taarabt was starting to have an increasing influence on the game, causing the hosts all sorts of problems with his direct approach.
But Mackie was continuing to look the likeliest to open the scoring as he was again thwarted by De Vries after springing the offside trap.
The Swans continued to look dangerous on the counter-attack, though, as Scott Sinclair fired just wide after good work from Pratley.
Pratley came agonisingly close to putting his side ahead in the 75th minute, only to see his effort cleared off the line by Ephraim.
Taarabt then picked up a yellow card for a cynical challenge on Joe Allen, prompting Warnock to withdraw his talismanic midfielder.
But the change did not make any difference as the game petered out into a draw.