All the goals came in the first half. Recalled Marcello Trotta fired the Reds ahead but two goals from Paddy Madden put the visitors in front before the break and that’s how it stayed.
It was also a bad day for Barnsley scorer Sam Winnall, Scunthorpe’s top scorer last season who went off with a pulled hamstring midway through the first half.
Trotta was introduced as Barnsley went 4-3-3 against the Iron, who continued with a 4-2-3-1 formation, and he smashed the ball into the roof of the net in the 29th minute after overlapping left-back Joe Dudgeon cut the ball back.
There was no time for the Reds to celebrate as Ross Turnbull beat down a shot from Gary McSheffrey only to see Madden hook home the equaliser within a minute.
Then Barnsley back-pedalled in stoppage time and Madden took advantage of a fortuitous rebound off Lewin Nyatanga to drive the Iron in front.
The Reds pressed after the break and substitute Jean-Yves M’voto was inches away from converting a free-kick from Conor Hourihane and Devante Cole smashed a shot over the bar after showing great control.
Scunthorpe’s best efforts came from shots from outside the area from Lyle Taylor and Luke Williams, which Turnbull parried away.