The Dons have now failed to win in their first five home games of the season after a Derek Riordan double proved to be enough to give the visitors all three points.

However, Calderwood questioned referee Mike McCurry's decision not to punish Souleymane Bamba after the Ivory Coast international gave away a penalty for fouling Lee Miller who looked to have been in a goal-scoring position.

The Dons boss also felt Charlie Mulgrew was unfortunate to have been given his marching orders by McCurry for handling on the line when Steven Fletcher appeared to have been in an offside position.

Calderwood said: "I thought Mike McCurry did well but if he has given us a penalty and it is a goalscoring chance, then the lad (Bamba) should be sent off, although you don't want anyone to be sent off. I think that decision could have changed the whole game.

"In the second half I felt we dominated again but they got the penalty. Seemingly the boy (Fletcher) was offside but Charlie has been sent off for us.

"If the assistant referee has seen that he is offside then we keep one of our best players on the park and the score stays level."

Calderwood refused to be critical of his team, despite them having now lost five matches in a row.

He said: "I don't think I can ask any more from the players.

"They kept going forward and no-one was hiding today. Obviously we need to cut out the individual mistakes but I can't knock them for their effort."

Hibernian boss Mixu Paatelainen wanted to see the penalty incident that led to Riordan's winner again before deciding if the Easter Road side had profited from a refereeing mistake.

"It was definitely a handball from Charlie Mulgrew," he said. "I don't know if our player was offside, it is difficult for me to say, but the referee gave a penalty which Derek converted."

Paatelainen praised the impact that second-half substitute Dean Shiels had on the game after replacing Steven Thicot.

"It took me about 10 minutes to decide who to take off for Dean but once he came on I felt he totally changed the game," the Hibernian manager said.

"He was very lively and got on the ball to make things happen for us."

The win sets Hibernian up nicely for their Edinburgh derby against Hearts after the international break on October 19.

Paatelainen added: "I'm delighted we won. We came here to take all three points and thankfully we did that."