Salford City manager Karl Robinson insists the PGMO has ‘a lot to answer for’ after his side were denied a penalty against Crawley Town.The incident in question occurred just after the hour-mark when Salford striker Daniel Udoh was brought down inside the box by Crawley’s Charlie Barker.Robinson guided Salford to a historic season but it’s hit a sour noteGettyUdoh attempted to control the ball after it was cut back from the right wing and attempted to roll it to the left.However, the Nigerian was wiped out by Barker, who did not win the ball.Unfortunately for Salford, referee Lee Swabey was unmoved.How non-penalty call cruelled Salford’s automatic promotion hopesSwabey’s choice not to award a penalty left Robinson and his troops apoplectic, especially since a victory for Salford would have secured them automatic promotion to League One.Instead, the result remained 0-0, with Salford finishing fourth in League Two with 81 points.Had they beaten Crawley, they would have ended the regular campaign with 83 points and gone above Cambridge United, who secured the last automatic promotion spot in the fourth tier courtesy of a 0-0 draw away to Crewe Alexandra.Instead, Salford must now settle for the play-offs, where they will face Grimsby Town in the semi-finals.Robinson: ‘Worst penalty not given for a long time’Speaking to talkSPORT after the contest, Robinson let rip at referee Swabey, who made the ‘biggest mistake of the whole day’.“I thought we were good,” Robinson said.“I thought we missed multiple chances.Udoh was brought down by Barker, but a penalty was not givenSky Sports“I guarantee if you look at any talkSPORT app or Sky Sports app or any media app, you’re going to see the worst penalty not given for a long time. “The referee has missed, he hasn’t missed it. He’s chosen not to give, so I’ve just seen him in there. It’s horrific.“I couldn’t have a go at him, but we missed chances. I thought we were good, I thought we were territorially dominant. I think we hit the bar twice in some ways. We missed open goals, we missed all of those things which fall on our toes. “But then when it comes down to the referee, he’s made the biggest mistake of the whole day.”Robinson, who led Salford to their highest-ever finish in club history and a fourth-round berth in the FA Cup, which is their deepest-ever run, added: “I don’t think Salford get the rub of the green enough.“The PGMOL have got a lot to answer for. A lot to answer for.Robinson didn’t mince his words about the refereeing performanceGetty“Because we spend money on players, our fans spend money, they’ve come all the way from Salford to support their team.“That penalty is horrific. It’s horrific. This week, the biggest stage, there’s been controversial penalties given and not given. That’s four penalties in one.“You can be in whatever level of football in the EFL, that is as blatant as you’re going to get. He (the referee) doesn’t even know what I’m moaning over.”When is Salford’s play-off semi-final?Robinson and his side must now put the Crawley debacle behind them as they travel to Blundell Stadium for the first leg of their play-off semi-final against Grimsby on May 10.Salford then host Grimsby at the Peninsula Stadium on May 15.