CAPE TOWN, Jan 3 (Reuters) - Quinton de Kock completed his third test century to help steer South Africa to a first innings tally of 392 as their tail enders frustrated Sri Lanka on the second day of the second test at Newlands on Tuesday.
South Africa were eventually all out just after the first session was extended with teenager Lahiru Kumara claiming six wickets.
De Kock, who was 68 not out overnight, drove the first ball of the day for four and brought up his century in 122 balls, albeit with a streaky shot edged down to fine leg.
The 24-year-old played an instinctive innings, full of quality shots, but will be disappointed he departed just two balls after reaching the landmark, edging Kumara behind to wicketkeeper Dinesh Chandimal.
His 101 added to Dean Elgar's century on the opening day on Monday to give South Africa a handy first innings tally after they had been in trouble early on, put into bat after losing the toss.
Kumara, brought in to strengthen the Sri Lanka attack after their defeat in the first test, claimed his first five-wicket haul in tests and also removed Vernon Philander for 20. The 19-year-old finished with figures of 6-122.
Philander and Keshav Maharaj had put on 40 runs for the ninth wicket to further drain a tired-looking Sri Lanka attack.
When the ninth wicket fell, lunch was put back by 30 minutes, but Sri Lanka were only kept in the field for a couple more minutes before Kagiso Rabada was the last wicket to fall, the sixth victim of Kumara in just his third test.
Maharaj finished unbeaten on 32.
South Africa resumed on 297 for six and added 95 runs to their tally on Tuesday.
Kyle Abbott was the first wicket to fall on the second day, failing to add to his overnight score of 16. He edged Rangana Herath to Chandimal, who took over the gloves from Kusal Mendis.
South Africa lead the three-test series after success in Port Elizabeth last week when they beat Sri Lanka by 206 runs.
The third test is at the Wanderers in Johannesburg from Jan. 12-16. (Reporting by Mark Gleeson; Editing by Sudipto Ganguly; firstname.lastname@example.org; +27828257807; Reuters Messaging: Reuters Messaging: email@example.com)