Hunt netted the opener three minutes prior to half-time before substitute Neil Harris equalised for the Lions within a minute of coming on. But Long scored the winner nine minutes later, drilling home his 16th of the season from the edge of the box to move the Royals to within seven points of the play-offs.
"His (Long's) partnership with Noel Hunt works well," said McDermott.
"When I was chief scout I watched Noel play a lot in Scotland and he's one that defenders hate to play against.
"He didn't stop working. The last thing you want is someone to come to the Madejski Stadium and outwork us."
McDermott added: "That win was for the fans after our recent results. It was important to see the game out and we kept the ball well.
"Before the game we talked about urgency. We had a few reminders that you can't wait for things to happen and you have to make it happen."
Source: PA
Source: PA