(AFP) - Debutant Marnus Labuschagne dismissed Asad Shafiq but Pakistan were on course for a huge first innings score after reaching 417-5 at tea on the second day of the first Test against Australia in Dubai on Monday.Shafiq was in sight of a 12th Test century but fell on 80 to leg-spinner Labuschagne, who had him caught behind with a ball that turned and caught the outside edge as the pitch showed a rare sign of spin.Shafiq hit nine boundaries and a six during his 212-minute stay and added 150 for the fifth wicket with Haris Sohail who was unbeaten on a career best 88.Babar Azam was the other unbeaten batsman on three.Left-hander Sohail struck his third half-century in six Tests. His previous best of 76 came on his debut against Sri Lanka in Abu Dhabi last year.It was another grind for the Australian bowlers as they only managed to dismiss nightwatchman Mohammad Abbas in the first session, bowled by fast bowler Peter Siddle after Pakistan resumed at 255-3.Siddle is the best Australian bowler with figures of 2-47 while Nathan Lyon, Labuschagne and Jon Holland have a wicket each.Both Lyon and Holland bowled in tandem but have yet to pose serious problems for the batsmen.The second and final Test will be played in Abu Dhabi from October 16.