Livingston boss David Martindale revealed he received an apology from referee Don Robertson after a 'stonewall' penalty wasn't given in their agonising Scottish Cup exit to St Johnstone on Monday night. The Lions were dreaming of a first Scottish Cup semi-final in 21 years when they welcomed Premiership side Saints to West Lothian and despite a dominant first half, they were undone by a Graham Carey wonderstrike in a narrow 1-0 defeat. That didn't tell half of the story though, as Lions passed up a number of big chances and Andrew Shinnie was struck in the face by Daniel Balodis' flailing arm inside the box. The officials failed to spot the incident at the time, but Robertson has since said sorry to Martindale for missing a potentially pivotal moment in the tie. Martindale knows the match was there for the taking and while he feels sorry for his players, he heaped praise on their efforts. He said: "I'm disappointed for the players more than I am for myself. They put a lot into the game and I thought they were brilliant in the first half, controlling the game and creating some very good chances. "Andy Fisher [the Saints goalkeeper] has come up with two big saves, one from Danny Wilson and one from Andrew Shinnie. "Then there is a stonewall penalty that we have had an apology for from the referee. "We can see from the dugout it is a stonewall penalty, so how the linesman can't see it I don't know. "If it is a penalty, I would argue it wasn't a genuine attempt for the ball so it would be a red card as well - there's a game-changer there. "Shinnie has a chance where he is clean through and doesn't hit the target and Robbie doesn't work the keeper with his effort. "We've had five big chances but I thought the group were brilliant. I'm really proud of the players, they played some fantastic football at times, and we created enough chances to be in the semi-final. "On another day, the officials make the right decisions during the game, not after it, so I think we can feel a bit sorry for ourselves in that respect. Big moments went against us, but the players should hold their heads high." Martindale was left ruing his side's failure to turn their chances into goals, but admitted there was nothing they could have done to stop Carey's 73rd minute winner which set up a semi-final with holders Celtic. He added: "The game came away from us for a wee 20-minute spell in the second half, where we couldn't get to grips with the game. We were losing a bit of momentum, a bit of energy, because we put a lot into the first half. "We lost the game to a wonderstrike. It is not a great way to lose any game of football but I think you can come to terms with it a wee bit easier because nobody is at fault. "Danny Wilson has a good header to clear it but it drops perfectly to Graham Carey's left foot and you are really wanting him to shoot from there, to be honest. But he scores and Jerome Prior is not at fault either, trying to save it. You don't see that kind of strike every week. "That knocked us a wee bit and we never quite got momentum after that."