Hashim Amla is set to make his 100th Test appearance for South Africa in the third Test against Sri Lanka in Johannesburg, live on Sky Sports 2 HD from 7.55am on Thursday.
Amla - who is set to become the eighth South African to reach a century of Test caps - has already amassed 7,665 Test runs, with 25 tons and a top score of 311 not out against England at The Oval in 2012.
However, the 33-year-old has struggled for form in recent months, going 12 innings' without a hundred and nine without a fifty, scoring just 195 runs across his last five Tests. His average has also dropped below 50, but his team-mates aren't concerned.
"He has a wonderful sense of calm," said opener Stephen Cook, who played with Amla in the national U19 side.
"When a situation becomes tricky or some of the players become a bit hot-headed, Hashim will be the guy who'll bring balance back.
"He's a fantastic person. You can look up the stats and read all the records he has but that only tells half of the tale.
"The person behind the batsman is more important to me. I was taught you're a human being first and then a cricketer. Hashim epitomises that."
South Africa will be looking for a win in Johannesburg to secure a 3-0 series whitewash, though Sri Lanka's Dhananjaya de Silva is hopeful they can again keep Amla quiet.
"He's a brilliant player, but he's not in form in this series. We hope it will be the same in this match as well," he said.
Sri Lanka have struggled with the seam movement on South Africa's pitches so far on their tour, failing to pass 300 in any of their four innings, and are unlikely to have any respite at the Wanderers, where Stuart Broad took 6-17 for England in their Test win at the venue last year.
South Africa, however, will have to do without fast bowler Kyle Abbott, after he shocked his fellow players and team management with the news that he has signed a Kolpak contract to play county cricket for Hampshire in England.
Abbott's contract with Cricket South Africa was immediately cancelled, and uncapped quick Duanne Olivier has been called up to the squad in his place, though it is expected Wayne Parnell will play at the Wanderers.
South Africa squad: Faf du Plessis (c), Hashim Amla, Temba Bavuma, Stephen Cook, Theunis de Bruyn, Quinton de Kock (wkt), JP Duminy, Dean Elgar, Kevash Maharaj, Duanne Olivier, Wayne Parnell, Vernon Philander, Kagiso Rabada.
Sri Lanka squad: Angelo Mathews (c), Dinesh Chandimal (wkt), Kusal Mendis, Kusal Perera, Dimuth Karunaratne, Kaushal Silva, Dhananjaya de Silva, Upul Tharanga, Lahiru Kumara, Vikum Sanjaya, Nuwan Pradeep, Dushmantha Chameera, Suranga Lakmal, Dilruwan Perera, Rangana Herath.
Watch day one of the third Test between South Africa and Sri Lanka from 7.55am on Thuursday, live on Sky Sports 2.