Wigan boss Roberto Martinez has accused referee Howard Webb of inconsistency after seeing his 10 men slip to a 1-0 defeat at Sunderland.
Midfielder Jordi Gomez was sent off two minutes into the second half at the Stadium of Light for a lunging challenge on Black Cats full-back Danny Rose. Sunderland took full advantage within four minutes when Steven Fletcher scored the game's only goal.
Martinez, who is facing an FA charge over comments he made on Michael Oliver's handling of his side's 4-0 defeat by Manchester United earlier this month, said: "Jordi tackles as a striker tackles, showing the studs, but he never leaves the ground, it's not a two-footed challenge. I can understand why the referee gave it, but I think it's very, very harsh."
He added: "My disappointment is that (Sebastian) Larsson has made a worse tackle against (Arouna) Kone and is not even shown a yellow card. That's just as you want as a manager, you want consistency for both teams.
"At the moment, we are on the back of a few bad decisions and you just need to take it in football. It happens. You just hope that over the course of the season, you are going to get good calls coming in our favour even though now, we find it difficult to understand that's going to happen."
Opposite number Martin O'Neill admitted that the sending-off had changed the game, but said: "My first thought was it looked a bit harsh to begin with. Having seen it back, I'm not so sure that the referee had much alternative.
"Whether Roberto agrees or disagrees with it - it may have been a sending-off - but I think his main point was that maybe it changed the dynamic of the game from that viewpoint because we reaped our reward pretty quickly. We scored soon after that and it gave us some impetus, a lot of impetus, in fact."
Wigan enjoyed the better of the first half with Simon Mignolet having to make early saves from James McCarthy and Kone, while McCarthy fired just wide two minutes before the break after Ivan Ramis had hacked a Larsson free-kick off the line at the other end.
However, the game changed two minutes after the restart when Gomez departed, and Fletcher cashed in when he turned home James McClean's driven cross to claim his fifth goal in four Barclays Premier League games.
The Scot's strike was enough to end a run of 12 league games without a win, and O'Neill was delighted said: "He did very, very well. He was brilliant today for us. Fletcher has come up big again for us, so eventually we have won the game, although it was edgy towards the end. But the win was vitally important for us and it keeps us going."