World No.1 Mark Anthony Selby of England was edged out by Northern Ireland-based Mark David Allen 5-6 at the semifinals of World Snooker Haikou Open on Saturday.

Selby made a mistake after opening up a break of 19 points, but Allen did not seize the chance, leaving Selby to claim the first frame with a run of 112 points.

Selby continued to make mistakes when facing the defense from Allen in the second frame, giving the opportunity for Allen to win it. But Allen lost his form in the next two frames as Selby fought back to claim a 3-1 lead to enter the mid-session interval.

During the fifth frame, Selby lost concentration again, leaving Allen to have a run of 105 points to make it 2-3. However, Selby came back to make a break of 102 points in the sixth frame to enlarge it to 4-2 and also successfully got through the defense from Allen in the seventh frame to have a break of 59 points, making a 5-2 lead.

Allen shrugged off a strong comeback to have a run of 80 points in the eighth frame and also won the next two frames.

Allen's sound form continued in the last frame with a break of 112 points to claim the victory.

"I feel disappointed to lose the game and my opponent played very well. Also my mistakes left the chance for him to reverse the match," Selby said.

"I am very happy to win and I played well in the last four frames though I fell behind before," said Allen, who hoped to do better in the final.

"Whoever I will meet tomorrow, it will be a tough match, but I will try best," Allen added.