Glen Johnson maintains the penalty awarded against him during Sunday's 2-1 defeat to Manchester United was a harsh decision.

With the scoreline tied at 1-1, the full-back was adjudged to have brought down Antonio Valencia by referee Mark Halsey, allowing Robin van Persie to net the visitors' winner from the spot.

"I've watched it 50 times, not that I needed to - it's not a penalty," said Johnson. "I didn't touch him. I collided with Pepe, I didn't touch Valencia at all.

"The referee told me he had to give it. He thought I touched him. There was no point me arguing with him on the pitch afterwards because he had already given it.

"It's so frustrating because I've not touched him."

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Liverpool were denied a spot kick of their own earlier in the contest when Luis Suarez went down under a challenge from Jonny Evans.

TV replays confirmed there was contact between the United defender and the Reds No.7.

Johnson continued: "I almost guarantee that if you flip it and Luis was the one who I was chasing and it's exactly the same situation with Luis rather than Valencia, then it wouldn't have been a penalty.

"We all know that. Reputations go in front of people at times. I know it's difficult for the referee when players are sprinting as fast as they can but in the big games those decisions are the difference.

"We expect referees to make the right decisions because we are working as hard as we can to win the game. To have it taken away like that, I can't explain it.

"Everyone has to do their job. They have to forget who they are looking at and make the decisions, not let anything from the past influence their decision. They have to call the shots at the time regardless of who it is."

Johnson's sentiments were echoed by Steven Gerrard, who is adamant the Reds should have been awarded a penalty for the incident.

The captain said: "Even when Luis does get fouled for a blatant penalty he might not get it. It's down to referees to not judge him and give what they see. If it's not a penalty don't give him one - but it was a penalty against United."