Neil Robertson outplayed a weary Ali Carter in the first session of their marathon last-four showdown as he began his quest to give Australia their first ever Crucible finalist.

The 28-year-old opened up a 6-2 lead over Essex cueman Carter in their World Championship semi-final, having had the benefit of an early-afternoon finish to his previous match.

By contrast Carter had a late night, taking out Shaun Murphy in a quarter-final decider, and then found it difficult to settle down and sleep.

The 30-year-old's start was sluggish as he lost the opening five frames and from that position to finish as he did was a minor success.

Robertson went 4-0 ahead after breaks of 124 and 91 and winning the third frame from a position where he required a snooker.

That lead was extended by a break of 76 in the fifth frame, but Carter eventually stepped up his performance.

He edged a tight frame before Robertson dominated the next.

Carter, runner-up in 2008, then had a fluke at the start of the eighth frame and went on a break of 38 before making a swift return and firing in 69 to trim Robertson's lead again.