Suarez added his second, Jon Walters replied before Daniel Sturridge ended a seven-week spell out with an ankle sprain to add the fifth right at the end.
"Soft, easy - any adjective you like really," said Hughes of the penalty.
"When players go down in the box the referee is going to have difficult decisions, we all know that, but I don't know whether that penalty would've been given at the other end.
"The reaction of the player himself, he immediately looks towards the referee, is a give-away and the fact there are about 3,000 Liverpool fans behind that goal as well reacting to it means unfortunately the referee has bought it and it's a poor decision.
"There was a hint of handball (by Sterling) and he has been given the benefit of the doubt.
"Given that we had come back from 2-0 down in the first half and got back on level terms I thought the momentum was with us and half-time came at a bad time as we were very much in the ascendency.
"Almost immediately the game is taken away from us once again. We had to show real character and determination to pick ourselves up from so many set-backs.
"I thought in terms of the performance I was really pleased but in key moments, and when you need things to go well for you you need to do the correct things at the right time they went against us.
"We needed to deal with key moments better defensively and we conceded a penalty and an own goal with a shot which was heading for the corner flag.
"It was a difficult day in terms of what went against us but I thought we showed real determination to keep on going because that augurs well for big games coming up."