Michael O'Neill believes his Northern Ireland side were not helped by referee Martin Atkinson during their "cruel" 1-0 defeat to Wales in Euro 2016.
Gareth McAuley's 75th-minute own goal ensured that it was Chris Coleman's Wales that progressed into the quarter-finals on Saturday, with Northern Ireland's tournament coming to an end.
However, despite the defeat O'Neill was delighted with the effort put in by his side.
"It hurts, it's a very, very cruel way to lose the game. We didn't deserve to lose the game," he said in his post-match press conference.
"We felt if we kept [Gareth] Bale and [Aaron] Ramsey quiet, Wales would struggle to get momentum. We could have created more with our first-half dominance but we were fairly comfortable.
"When you're a small nation without world-class players you have to be strong tactically and make yourselves difficult to beat. We've certainly done that.
"I was disappointed towards the end in terms of the time-wasting and I felt the referee could have handled that better, but in terms of our display and how we played we couldn't have asked any more of the players."
During the second half, a collision between Wales team-mates Ashley Williams and Jonny Williams led to some confusion on the pitch, with the referee initially allowing play to continue to Northern Ireland's advantage before changing his decision.
"The [Wales] dugout told Ashley Williams to lay down on the pitch," said O'Neill. "The referee stopped the game and didn't make Ashley Williams leave the pitch. It's the first time I've seen that in my career.
"The referee's assistant was very aware. He heard the instruction for Ashley Williams to sit down.
"So I don't think four minutes injury time at the end was a fair reflection. We had six substitutes also in the game. I felt we deserved an extra couple of minutes to try and force an equaliser."
A major factor in Northern Ireland's rise to the forefront of Euro 2016 has been the fan-made chant for striker Will Grigg, who came into the tournament on the back of netting 20 league goals for Wigan Athletic in 2016.
But, in spite of the clamour for the 24-year-old to feature, he did not get a single minute under his belt, and O'Neill was quick to explain his decision.
"Will didn't get the opportunity to play. He was really our fourth-choice striker," he added.
"He's a good young player and he's got a bright future ahead of him but I don't pick my team around what the fans sing at the game."