A fortnight ago, Vedran Janjetovic lived that very nightmare, in front of a sell-out crowd and one the league's highest-ever TV audiences. His failure to quell a seemingly harmless scenario in the Sydney derby ended with an attempted clearance guiding the ball into his own net.

It was the kind of error that can shadow an entire career, let alone ruin a result. If you let it get to you, that is.

But since that moment, at the half-hour mark of round two, with his club trailing by two goals against their arch-rivals, Janjetovic hasn't conceded a goal. Sydney have scored five at the other end and now sit in second place, behind only Melbourne Victory on goal difference.

"It was a disaster," he told Fairfax Media, throwing his hands in the air. "For the team obviously, because it put us 2-0 down, but personally, because I made the error. We all make mistakes, that's part of the game, but I know it was me who cost us. That's a terrible feeling to have, even if there's nothing you can do. After that it's tough because the crowd gets on your back. In those moments, that's when you enter the mental game with yourself."

Perhaps his quick recovery from the howler makes it easy for Janjetovic to talk about – and openly accept his share of the blame.

"I think it was Sasa [Ognenovski] who tried to clear the ball but it went really high and it had this spin on it. It was so unpredictable, going left, then right, and back again," he said. "I was standing underneath it and when I thought I had it covered, I jumped to claim it. But as soon as I jumped, it swung to my right, away from me, and then a bunch of players came in. But I'm not going to say someone pushed me, simply because I should have stopped it. I can't make excuses. I made a mistake. I put my hand up.

"But the best keepers in the world make mistakes, that's just how it is. I was just praying we got one goal back before half-time, which we did, and said a few more prayers that we'd get a second. When we got that, and then scored the winner, it was a blessing. I can't tell you how relieved I was."

There's two schools of thoughts when it comes to dealing with calamities. One is to scrutinise the mistake forensically, the other to move on as quickly as possible at the risk of it becoming a permanent scar.

"When you're a goalkeeper, you need to work out what the error is before you decide how you deal with it," Janjetovic said. "We worked out that error came down to a misjudgment. A one-off – something you wouldn't expect to happen again. Of course, you want to learn and improve, but it's one you can't let affect you the next time you're in the same position.

"If it was a technical issue, I'd sit down with [goalkeeping coaches] Davide [Del Giovine] or "Spider" [Zeljko Kalac] and we'd analyse it. Last year, a couple times we had to consider some moments and it's usually just the small things – getting your feet in the right direction, your positioning, all that."

With Ivan Necevski taking his place between the posts a few days later in the FFA Cup quarter-final with Adelaide United, which Sydney lost 3-1 in extra time, there was some nervous moments as the squad was named to face Brisbane Roar at Suncorp Stadium.

But Janjetovic was back between the posts, a clear sign of faith from Graham Arnold. He repaid the coach by keeping his first clean sheet of the season against a Roar side considered among the A-League's most potent.

"Arnie has been desperate for us to keep clean sheets as much as we can. Obviously that's not always possible but in the games that you do, it certainly gives you a much better chance of winning and, if nothing else, guarantees a point," he said. "That's been our emphasis defensively and to get it against Brisbane, on their turf, was like getting the monkey off the back. We defended together, from the front. That was a total team performance.

"Now we've got Central Coast and I don't see why we can't go two clean sheets in a row. Then five in a row. Who knows, but I don't see why we shouldn't try."