United’s captain praised a persistent performance and admitted he was confident of Leeds bridging the gap to sixth place during their 12 remaining Championship games.
The Elland Road club ground three points out of a competitive meeting with Millwall on Saturday, with Warnock striking on 71 minutes after Ross McCormack’s earlier penalty was saved.
A third successive clean sheet ensured that the left-back’s finish was enough to win the game, though United failed to cut the gap to the play-off zone as a win at home to Huddersfield Town kept Gus Poyet’s Brighton six points clear.
But Peltier said: “I thought it was a very good performance and it’s a massive three points.
“Every game is massive for us now but I’d rather be going into the play-off places coming in from the outside than being in there and under pressure.
“You see every year that there’s a late charge from someone and hopefully that’s us.
“For the past five or six weeks now we’ve been playing really well but sometimes the results haven’t gone for us. It did this time.”
Warnock stepped up to take the decisive penalty following McCormack’s unsuccessful effort midway through the first half. The Scotland international saw a low finish turned onto a post by Millwall goalkeeper David Forde.
Manager Neil Warnock considered introducing El-Hadji Diouf as a substitute after referee Mike Jones awarded Leeds a second spot-kick but Peltier said: “At half-time I chose Stephen to take a penalty. I asked him if he fancied it because I know he’s got so much quality in his left foot. So I’m taking the credit!
“The gaffer was going to put Dioufy on but I said ‘no, Stephen’s taking it’. I wouldn’t say I overruled him. I just pointed out that I’d already asked Stephen and he said ‘yes’. Thankfully he scored it.
“I don’t think he’s ever taken a penalty as a professional.
“It’s a brave thing to do but he’s experienced so you’d expect him to be able to step up.”