COLOMBO - Sri Lanka beat Pakistan by 16 runs in the first semifinal of the World Twenty20 at the R Premadasa Stadium on Thursday.The hosts posted 139 for four wickets and then returned to restrict Pakistan to 123 for seven to book a place in Sunday’s final where they will meet either Australia or West Indies. For Sri Lanka, Rangana Herath (3-25), Ajantha Mendis (2-27) and Angelo Mathews (2-27) shone with the ball to defend a modest total.Opting to bat first, Sri Lanka could not make the most of a strong start provided by skipper Mahela Jayawardene (42) and Tillakaratne Dilshan (35) but still posted a competitive score on a turning track.Dilshan hit three boundaries in his 43-ball innings before Umar Gul trapped him leg before in the 18th over. For Pakistan, Mohammad Hafeez, Umar Gul, Shahid Afridi and Saeed Ajmal claimed one wicket each.Scores: Sri Lanka 139-4 in 20 overs (Mahela Jayawardene 42, Tillakaratne Dilshan 35) v Pakistan 123-7 in 20 overs (Mohammad Hafeez 42; Rangana Herath 3-25, Angelo Mathews 2-27, Ajantha Mendis 2-27).