First-half goals from Theo Corbeanu and Florian Kamberi put Wednesday in control at Hillsborough, before Lee Gregory added a third after the interval.
The result means Sunderland remain fifth in League One, albeit with a game in hand on each of the four teams above them.
Yet two heavy defeats against Rotherham and Wednesday have raised serious concerns on Wearside following a promising start to the campaign.
The Black Cats will now have to wait nearly three weeks until their next league game against Ipswich on November 20, due to their FA Cup fixture and international call-ups.
But which sides are finding form, and which sides have hit a sticky spell?
We’ve taken a closer look at the League One form table, including each team’s last six league games to see where they all rank.
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1. Rotherham - 18 points
Won: 6 | Drawn: 0 | Lost: 0 | Goals scored: 12 | Goals against: 0 Photo: George Wood
2. Bolton - 16 points
Won: 5 | Drawn: 1 | Lost: 0 | Goals scored: 15 | Goals against: 4 Photo: Charlotte Tattersall
3. Ipswich - 13 points
Won: 4 | Drawn: 1 | Lost: 1 | Goals scored: 6 | Goals against: 2 Photo: Stephen Pond
4. Sheffield Wednesday - 12 points
Won: 4 | Drawn: 0 | Lost: 2 | Goals scored: 8 | Goals against: 5 Photo: George Wood