The Royals moved into the top six at the weekend and saw off a strong challenge from a spirited North End side to move three points ahead of seventh-placed Nottingham Forest with seven games left.
McDermott's side go to the City Ground next weekend in a potentially decisive fixture and saw his side win their fifth league game on the spin when substitute Hal Robson-Kanu looped in an 82nd-minute winner.
He said: "We went for the win and we got it but that was a tough game. Their record has been very good and Phil Brown has done a fantastic job. They will give everyone a game between now and the end of the season.
"We hit the bar, had one off the line, maybe could have had a penalty and had chances late on so we are happy we were able to sneak one in there.
"We have momentum going for us now and it's about winning games at this stage of the season. We know we have some very tough games left between now and the rest of the season and it will go to the wire. We go to Nottingham on Saturday which is obviously a huge game and I will pick a team to win there."
Source: PA
Source: PA