He was beaten 5-3 by England's Michael Wesley in the event, which is being held in St Petersburg in Russia.
Wesley took the first frame with a 53 break, however, a great pot on the last red in frame two allowed Carlisle to level at 1-1.
An excellent clearance in frame three put Carlisle ahead before Wesley levelled before the interval thanks to a break of 62.
The next went to Carlisle but it was to be the last frame he would win as Wesley took the next three frames to seal a 5-3 victory.
But, overall, Robert was delighted with his performance in such a major event.
Fourteen-year-old Belgian wonderkid Luca Brecel, went on to win the final 6-5 against Wesley on the black.
However, as Brecel is too young to enter the main tour, victory for Carlisle in the semi final would have been enough for him to secure entry to the WSA Main Tour as runner-up..