The R's captain was replaced midway through the second half by Jamie Mackie, who snatched a last-gasp winner against the Reds having been 2-0 down.
Barton’s departure was met with cheers from the home crowd, who booed him off the pitch when his number went up on the fourth official's electronic board.
"I was awful tonight," Barton said via his Twitter account. "Worst I've ever played in my career.
"But we WON.......and that's the most important thing. Onwards and upwards.
"Disappointed with fans booing, [we are] meant to be in it together.
"They won't break me, guaranteed. I've been through much worse.
"Enough of the negative **** anyway. What a ******* result, great spirit shown by the boys and loyal fans tonight. Not the bells that booed."
The 29-year-old later posted: "Form is temporary, class is permanent."
QPR manager Mark Hughes was questioned about the reception Barton received after the match, but claimed to have not noticed it.
"I was not aware of that," Hughes said. "Joey was not having the best of times.
"It was unfortunate that maybe a few felt the need to possibly boo him, but Joey is very strong as we all know.
"He won't let it affect him and he will play a big part in what we do from now until the end of the season.
"Tonight was not his night, but there will be other nights."
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