West Bromwich Albion emerged unscathed at a ground where their promotion rivals Newcastle have already succumbed this season, but Roberto di Matteo's team only triumphed after the award of two penalties – one of which they missed – and the dismissal of two Scunthorpe players.
Yet Albion should not have needed any assistance from the decisions of referee Jon Moss, who got most of the big ones right – even if the Scunthorpe crowd would not agree.
The visitors briefly wobbled, but the dismissal of Andrew Wright, swiftly followed by a red card for Grant McCann, tipped the game in their favour and keeps them on course for a swift return to the Premier League.
The referee was the focus of attention at the end, with Di Matteo insisting: "He had a good game. He was in a good position to give both penalties. This is a difficult place to come and we have to be pleased with our performance, but the first sending off gave us the edge. We needed to stay calm because the crowd tried to influence the ref."
Scunthorpe manager Nigel Adkins was less content, but stopped short of blaming the official for a defeat that leaves them in trouble. He said: "I've got to be careful what I say. We have to live with the decisions he made but I was very disappointed with the Andy Wright dismissal. It was the turning point. It's disappointing, but that's life."
It should not have been this difficult for Albion who had dominated the first 45 minutes of the game. The Baggies, the most prolific scorers in the division, emphasised their attacking outlook with a neat move that ended with Scunthorpe keeper Joe Murphy saving well from Jerome Thomas after only 47 seconds. It heralded an enterprising spell from Di Matteo's team, who were not to be denied their deserved lead for long. With 19 one-sided minutes gone, Murphy palmed another Thomas cross straight to Graham Dorrans, who finished decisively.
For the rest of the half Albion's superiority in every area was not seriously questioned, but with just 45 seconds of the second period gone, the visitors were caught dozing. Josh Wright collected a short corner but his shot was saved by keeper Dean Kiely. The rebound fell straight to Rob Jones, who reacted quickly to claim his first goal for the club since moving to the club from Hibernian in the summer.
It prompted a brief spell of pressure from Scunthorpe, but their fate was settled on the hour when they were reduced to 10 men after Wright collected his second yellow card. Albion were ahead again within five minutes when Dorrans scored from the penalty spot after being brought down by Michael O'Connor.
Then the 10 men became nine when McCann saw red for dissent after the award of a second penalty. He should have saved his breath – Dorrans' hat-trick bid was foiled by a fine save from Murphy. Despite that disappointment, Albion made sure of the points with a late goal from Gianni Zuiverloon.
Scunthorpe United (4-5-1): Murphy; Williams, Mirfin, Jones, A Wright; Thompson (Forte, 83), J Wright (Woolford, 54; May 87), Togwell, O'Connor, McCann; Hayes. Substitutes not used: Slocombe, Sparrow, Spence, Canavan.
West Bromwich Albion (4-4-2): Kiely; Zuiverloon, Meite, Olsson, Cech; Brunt (Martis, 87), Jara, Dorrans (Mulumbu, 77), Thomas; Cox (Wood, 63), Moore. Substitutes not used: Allsop, Bednar, Reid, Teixeira.
Referee: J Moss (West Yorkshire).