But when he did get going the left-hander stormed back from 4-2 behind to snatch a memorable 5-4 victory, just when it looked like he was going home early from the Waterfront Hall in Belfast.

Murphy made a fantastic start to the match with breaks of 72, 134 and 99 to take the first three frames.

The Rotherham potter also led 43-0 in the fourth frame before Robertson launched his recovery.

Runs of 57 and 59 drew the former world under-21 champion within one frame, then Murphy went 4-2 up with a superb 133. Still Robertson battled on, rattling in 69 and 85 for 4-4.

The deciding frame was finely balanced at 30-28 when the Melbourne player blasted in a long red to initiate a decisive 53.

“I was 3-0 down without doing anything wrong, Shaun just potted some great long reds and made some big breaks,” said 23-year-old Robertson.

“I still felt very good and I had a lot of belief in my ability to get back into the match.

“It was very similar to a game we played in the UK qualifiers last season [which Robertson won 9-8], in fact the standard today was probably even higher.

“I’ve been to three quarter-finals before so I’m very pleased to get through to a semi this time. Quinten [Hann] was in seven or eight quarters before he won one, it can be a tough barrier to get through. I feel very good about my chances.”

Robertson will now face Matthew Stevens, who survived the loss of his cue tip to record a 5-2 victory over Scotland’s Stephen Maguire.

UK champion Maguire led 2-1 after breaks of 60 and 55.

Midway through the fourth frame, the tip flew off the top of Stevens’ cue. A premature interval was called as tournament director Martin Clark hastily replaced the tip.

The Welshman went on to win the frame and added the next three with runs of 68, 52 and 47.

“My tip has only ever fallen off twice – the first time was against Stephen at the British Open last year, but that time I lost 5-0!” said world number four Stevens, who lost 18-16 to Murphy in the Crucible final in May.

“It’s good for me to get a couple of results early on because last season I didn’t win a match until well after Christmas.

“I only had five or six practice sessions before this event but I feel great. Losing the world final is history now, I’m only looking forward.”

Tonight’s other quarter-final clashes (7pm start) will see seven-times world champion Stephen Hendry take on world amateur champion Mark Allen, while fellow Irishman Joe Swail meets Scot Alan McManus.