John Sheridan felt his Wigan side were robbed of a stoppage-time penalty in the 3-2 home defeat to Gillingham in Sky Bet League One.
The 55-year-old was taking charge of the Latics for the first time at the DW Stadium after taking over last week, and saw Joe Garner open the scoring midway through the first half.
However, two goals from Jordan Graham and one from Trae Coyle gave Gillingham a commanding advantage before Kal Naismith pulled one back.
Sheridan felt Wigan should have been given the chance to equalise with seconds to go, after substitute Olly Crankshaw’s cross appeared to hit the hand of a visiting defender.
“It was a stonewall penalty, I’ve seen it and it was absolute stonewall,” Sheridan claimed.
“Coming so late, it obviously would have given us a chance of a draw in the game. But it wasn’t to be, and we just have to move on as quickly as we can.”
Wigan have now lost all three of their matches in all competitions this season, but Sheridan was far from downhearted with what he saw.
“It’s tough to take,” he said. “In my first home game I’d have loved to have got off with a positive result.
“I have seen good signs again, I thought we actually played all right in the game.
“But the bad signs are the manner of the goals we’ve conceded – very, very, very poor.
“We knew exactly what they are all about – they play forward, with long throws, put you under pressure, get big players into the box.
“To concede the first goal so soon after taking the lead is poor. Then they get the second, and we’re disappointed to go in at half-time behind.
“I was quite pleased with the way we played in the second half, we were positive and brave without really having a cutting edge about us.
“I thought we were moving the ball around with very little danger at our end. But again out of the blue, against the run of play, we concede a third goal and it’s even harder.
“Overall there were some good performances, but we need to do better with the goal situation at the other end.”
For Gills boss Steve Evans, it was a very productive long trip north.
“We’ve got three points on the board,” Evans said.
“We’re younger this season and more athletic. I think after they got the second goal we saw it through really well.”
On his two-goal matchwinner, he added: “Jordan is very effective and purposeful.”
Graham himself was pleased with his afternoon’s work.
“It’s a feeling I was excited to have,” he said. “We’re starting to show signs that we can play.
“It’s good for me, I want to keep adding goals to my game – I don’t score enough.”