Paynter scored his first two Elland Road goals as United saw off Peterborough 4-1, laying to rest a home drought that has existed ever since he signed from Swindon in the summer of 2010.
He had scored just once in 26 appearances prior to today and when his name was read out prior to kick-off, it was greeted with sarcastic cheers from supporters who have grown tired of waiting for the 27-year-old to prove what Warnock’s predecessor, Simon Grayson, saw in him.
He answered them with two goals - albeit one from a yard - and could have had a hat-trick.
But, despite affording Paynter a standing ovation when he substituted him with a minute left, Warnock, who has promised major summer surgery to the squad he inherited from Grayson, could not promise the forward would still be at the club come August.
“I don’t get carried away, nothing has changed my opinion on what I need,” Warnock said.
“I haven’t got a clue (if Paynter will stay). I don’t think anyone can tell me who is going to be involved but I think you would be an idiot if you wanted to leave.
“But I was pleased for Billy. He did ever so well. He’s been like that in training and that’s why I played him. It was a good opportunity, he’s been shining in training and I thought: ‘To hell with it’.
“I told him at half-time that he deserved his goal and he said: ‘Really gaffer? I thought I should have had a hat-trick’, and he could.”
Leeds had fallen behind to Joe Newell’s opener, before Paynter and Ross McCormack (two) turned things around in a 180-second spell either side of the break.
Paynter then wrapped things up, meaning the Whites avoided losing 11 home games in a season for the first time, while Warnock also picked up his first victory in front of his own supporters.
“It’s been a long time coming,” he added.
“We’ve had some great performances and some diabolical performances. We seem to be on a toss of a coin.”
For Peterborough, safety is still not assured even though they are rank outsiders for the drop.
Darren Ferguson’s men are eight points clear of third-bottom Coventry with three games remaining, and it would take a freakish set of results to see them make an immediate return to League Two.
The Scot knows anything can happen, though, and as a result was disappointed to see his side capitulate today.
“The first goal for Leeds changed the game,” he said.
“We could have been more than 1-0 up and were causing them all sorts of problems. But a crazy five minutes killed us. Some of our defending was comical.
“We’re making it hard for ourselves, we’re faltering at the death. We wanted to end with momentum, which might not seem important at the moment but it will next season.”
Ferguson also confirmed that defender Gabriel Zakuani will not play again this season owing to a dislocated shoulder.