It was a vital three points for Eriksson's men in the race for the npower Championship play-offs, while defeat kept the home side four points from safety at the bottom.
Defender Miguel Vitor opened the scoring in the 31st minute when Gallagher's corner found its way to him at the back post, and the Portuguese centre-back was at it again in the 72nd minute with a powerful header from a Gallagher cross. Four minutes later the scoring was complete when former Scotland international Gallagher caught out the Scunthorpe defence with a short free-kick and full-back Kyle Naughton curled a shot into the bottom corner.
Eriksson said: "Last Tuesday we lost to Norwich in a bad way. We have talked a lot about it since and we were very concentrated and showed aggression, we have come back in a brilliant way.
"With nine games to go, if we can show the spirit we showed, we won't lose many games and we'll win a lot.
"Gallagher's right foot is special, he is not far from Beckham in terms of his delivery of set-pieces."
Source: PA
Source: PA