Hammered 5-2 by Arsenal at the Madejski Stadium on Monday, Reading have collected just nine points from 17 games and conceded a league-worst 36 goals along the way.
The hosts were torn apart by an Arsenal side determined to make up for last week' shock League Cup exit at Bradford City, and while Reading gave a decent account of themselves in the second half it was too little too late.
McDermott said his side had to pull together if they wanted to stay among England's elite.
"We were out of the league for four years and we'll be doing everything in our power to be in this division next season," he told Reading's official website. "Don't write us off."
Lukas Podolski put Arsenal ahead after 14 minutes before Santi Cazorla scored twice before the break and once after to give the visitors a 4-0 lead.
Adam Le Fondre and Jimmy Kebe gave the home fans a glimmer of hope with second half goals but Arsenal's Theo Walcott wrapped up the match in the 80th minute.
McDermott, named 2011/12 Championship Manager of the Season after leading Reading to the division title, said it had been a dangerous time to play the Gunners.
"We've caught them when they've just been beaten by Bradford, that would have hurt so they were right up for it and they have got top drawer players who cost fortunes.
"So it was never going to be easy and we conceded an early goal as well. I think they would have beaten most teams tonight."
Shipping soft goals has become a feature of Reading's season so far but McDermott said it was important to show the fans his team wanted to play attacking football rather than sit back and try to limit the damage.
"The fans got behind us again, second half they saw us having a real go. They'll forgive you as long as you're having a go," he added.
"We've played Manchester United and scored three, we've got another two tonight, three against Fulham, we're scoring goals so it's obvious where we need to sort out our team.
"It's another game with seven goals at Madejski Stadium and we want those goals to be in our favour."
Reading face a tough trip to champions Manchester City on Saturday but will be determined to pick up points at home against Swansea City and West Ham United after Christmas.
While some fans may wince at the thought of taking on the Premier League's big guns, McDermott looked forward to playing them. Those were the kind of games they had dreamed of while battling for promotion from the Championship.
"We've had good times in the last three years, whether our fans would say these are good times I don't know," he said. "Playing Manchester United, City, Arsenal, personally I think those are good times.
"My belief is that things will change. I'm not enjoying the results but I'm enjoying the challenge." (Reporting by Peter Rutherford in Singapore; Editing by Patrick Johnston)
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