Veteran Khan battles on for Pakistan in Sri Lanka Test
Younis Khan (front) and Asad Shafiq (R) pictured during the opening Test match between Sri Lanka and Pakistan in Galle, August 7, 2014 - by Ishara S. Kodikara
Resuming at the overnight score of 261-4, the tourists revelled on the easy-paced wicket to move to 347-5 by lunch on the second day at the Galle International Stadium.
Khan, who came in to bat at 19-2 on the first morning and ended the day on 133, was untroubled by both Sri Lanka's seamers and spinners.
The 36-year-old, who is playing his 90th Test, has so far batted for eight hours, hitting 15 boundaries and a six in his 24th Test century.
Asad Shafiq made 75 during a fifth-wicket stand of 137 with Khan to consolidate Pakistan's position.
The visitors added 32 runs in the first hour when left-arm spinner Rangana Herath broke through for Sri Lanka by trapping Shafiq leg-before. The batsman's appeal to the TV umpire went in vain.
Sri Lanka came close to removing Khan when he was on 156, but seamer Shaminda Eranga spilled a sharp return catch as the batsman failed to keep a drive along the ground.
Pakistan wicket-keeper Sarfraz Ahmed was unbeaten on 28 at the break, having added 54 valuable runs for the sixth wicket with Khan.
Former Sri Lankan captain Mahela Jayawardene is due to retire from Test cricket at the conclusion of the two-match series.