The Hoops are currently bottom of the table and without a victory in 12 attempts after Saturday’s 3-0 loss to Southampton at Loftus Road.
Mark Hughes was critical of his players’ below-par performance as they struggled against their fellow contenders for the drop, and Nelsen admitted the Hoops must improve regardless of the opposition.
“Every game from now until the end of the season is a ‘stand up and be counted’ game,” Nelsen told QPR’s website. “When the pressure is on, players have to take responsibility.
“It doesn’t matter who you’re playing, the Premier League is just unforgiving. You’ve got to earn your right to play and win.
“You’ve got to be strong mentally and have the confidence to do something in the game at both ends of the park.”
Much of the focus has been on Hughes’ under-performing high-profile summer signings, including the likes of Julio Cesar, Esteban Granero and Park Ji-Sung.
But Nelsen insisted the talent in QPR’s squad is irrelevant in their current predicament, instead stressing the importance of qualities such as “mental and characteristic strength” ahead of Saturday’s trip to Manchester United.
“When the pressure is on, you can be the most talented players in the world but when the microscope goes on you, talent goes out the window,” he added.
“I believe we need more mental strength and hopefully we can then showcase the talent to go on to win games.”