The Royals were far from their fluent best for the majority of the 2-1 victory but found a late winner through winger Hal Robson-Kanu to open up a three-point gap over Nottingham Forest in seventh place.
Long said: "At the start of the season we seemed to be drawing games and we couldn't pull the results out.
"As a team we didn't perform to our best against Preston but we got the result we needed.
"I think that is what will help us get into the play-offs this season. It was a very big win for us.
"Confidence in the side is very high at the moment. It's a very easygoing club and the gaffer lets you express yourself on the pitch. People have that freedom to perform and it's doing us good so far."
Source: PA
Source: PA