[caption id="" align="alignnone" width="750"] Pakistans Younis Khan (left) congratulates Shan Masood after his half-century against Sri Lanka during the fourth day of their third Test match in Pallekele on Monday. Photo: AFP[/caption]Younus Khan remained unbeaten after a brilliant 171 as Pakistan beat Sri Lanka by seven wickets in the final test to win the three-match series 2-1 at Pallekele on Tuesday.Chasing a daunting 377-run victory target, skipper Misbah-ul-Haq (57) sealed the win hitting Jehan Mubarak for a six.Shan Masood (125) was the only wicket to fall on the final day of the pulsating test, and the Pakistan opener was out after adding 242 runs with Younus that turned the match on its head.Younus faced 271 balls in his marathon unbeaten knock, hitting 18 boundaries in his 11th 150-plus score, which is highest by any Pakistani batsman.