Alastair Cook was relieved to at last complete his 20th Test century, after a clutch of near misses.

Cook's unbeaten 114 on day one of the first Investec Test against South Africa at the Kia Oval was an emotional achievement for several reasons. It came only three days after Cook had attended the funeral of his former schoolboy opening partner David Randall, who died aged just 27 from cancer.

Cook was also moving level with his Essex mentor and England batting coach Graham Gooch, among others, in joint-fifth in his country's all-time list of prolific Test centurions. He said: "It was very satisfying."

It was an especially gratifying moment too, when he pushed Imran Tahir for a single to cover to move to three figures, because Cook has twice fallen just six runs short of a hundred since he made a career-best 294 at Edgbaston almost a year ago.

He shared a second-wicket stand of 170 with Jonathan Trott (71) in a stumps total of 267 for three, after Morne Morkel had Andrew Strauss lbw in the first over of the series.

Cook added: "When you come so close a few times - I think it's been a year since my last Test hundred - it makes it a very special moment.

"It's nice to join Goochie. Clearly he was a great player, and to have the same amount of hundreds as him is special."

Remembering his schoolboy friend from Maldon Cricket Club, it was evident Thursday's hundred was poignant for Cook.

"Clearly it was an emotional time, and when you score hundreds the emotions are right up there," he said.

"We are lucky enough to play cricket - unfortunately he can't."