Swansea City manager Garry Monk was critical of the officials after seeing his side beaten 3-0 by Arsenal at the Liberty Stadium on Saturday.
The hosts conceded all three goals after the interval - Olivier Giroud and Joel Campbell scoring either side of a controversial effort from Laurent Koscielny.
Swansea felt Giroud fouled goalkeeper Lukasz Fabianski prior to the Pole dropping the ball and Koscielny prodding home, while Monk's men were also denied a first-half penalty when Per Mertesacker appeared to handle Gylfi Sigurdsson's free-kick.
Monk, whose side were on top prior to sloppy defending for Giroud's opener, said: "It's the irony of football, you can play badly and win, and play really well and lose - today you could see the intention from us and we really should have taken our chances.
"It's a hard one because there were a lot of positives and in the first half we were the better team. We created chances, played the better football and then obviously we're disappointed in the first two goals.
"I've seen them [the Fabianski incident] given pretty much every time as a foul, possibly Fab could have punched it but I think he's got a point in terms of seeing them given time and time again.
"It depends what you expect from those type of decisions - I don't expect things to go for us but I've played in many of those decisions and whenever the keeper is touched it's a foul.
"But obviously it wasn't going to be that decision today."
Swansea have not won at home in the league since the end of August, with the lack of a penalty award for Mertesacker's apparent handball adding to Monk's frustrations.
"I knew it was handball but, when you see the replay, you see that it's intentional and you have to say it's a handball," he added.
"It's just a shame and I feel for the players because that first half was much better and more like ourselves. We were aggressive, on the front foot, creating chances.
"It's important we take that part of the game and go into the teams that are more to our level in and around us. Ultimately we're disappointed, especially in gifting those two goals at the start of the second half.
"I think 3-0 flatters Arsenal but you need to take your chances and get yourself on top when you are playing well.
"It's difficult because there's so many positives but ultimately we've lost the game."
