Matej Vydra missed a great opportunity to secure a victory for Reading last night, before Middlesbrough went up the other end to snatch all three points.
Captain Paul McShane and teammate Danny Williams had a visible confrontation during the second half.
In a lively post match interview with BBC Radio, McDermott also refused to blame Matej Vydra for failing to covert a fantastic opportunity to seal an away victory, before the hosts went up the other end and scored the winner.
"I didn't see it," he said. "But, I do know that these guys want to win. I've seen players in dressing rooms that have won leagues (doing things) that you wouldn't know about. I don't really want to talk about it. That's what winners do, they want to win.
"I'm not here to pillar one person. We're sick for Matej Vydra, we're sick that it hasn't gone in the net."
The Berkshire club have been on a poor run of form of late, with just two wins in their last eight Championship games, and they currently sit in 14th place in the league.
They require one more point to be mathematically safe from relegation, and that would explain why McDermott was so bitterly disappointed with losing the game at the Riverside.
"We're absolutely sick to lose the game," he added. "If we hit the target there, we win the game. It's a real disappointment that we haven't won the game."
Next up for McDermott's men is a trip to Elland Road to play Leeds United as they look to secure their Championship status and build momentum for next season.