If the ball is not hitting either the stumps or your bat it is very hard to get out in this game and Cook's 10th Test century was a masterclass in self restraint.
Cook - predictably known as Chef - pricked most people's consciousness when aged 20 he took 214 off the touring Australians in a day four years ago, described by a national newspaper as batting with "a freedom gifted to the few".
But after a bad trot that has seen him make just one half-century in last 12 Test innings, Cook today showed all the restraint of Lara Flynn Boyle at an all-you-can-eat buffet.
Cook silenced the critics with an educational innings - educational as it wanted you to read a book for large parts of it.
It was dull but hugely effective.
In beautiful batting conditions on the East Coast this morning, the Essex left-hander scored just one in the opening hour but preserved his wicket and went on to score his first century since a ton against West Indies in May at Chester-le-Street.
A 218 ball vigil that included 67 leave alones.
Cook has had enough of the dabble outside off - although having scored 118 we can forgive him for getting out in just that manner - caught a slip for the umpteenth time.
Chef is one of those poor sods whose birthday is on Christmas Day. As he opened up his combo DVD's at the tender age of 25 on Friday he knew that the following day he would be making his 50th Test appearance.
The youngest Englishman to reach that milestone and not really under any pressure for his place with no other recognised openers on the tour.
With Joe Denly and Michael Carberry the next opening cabs on the rank, those on the outside are hardly banging at the selectors door. Actually we're not sure they have even managed a polite knock.
Cook is a certain FEC (future England captain), looks destined for a century of England caps and you'll get short odds on him breaking Alec Stewart's record of 133 Test caps because as proved today even when he's not in great nick, he has the mental fortitude to work through any technical limitations.
Mental fortitude is something not usually associated with 'King of the Cameo', Ian Bell.
Bell reached the half-century mark for Tests at Centurion (still three months short of his 28th birthday) but that performance and in particular leaving a straight one from Paul Harris did nothing to quell those calling for his head.
For Bell every Test seems like his first with his average having dipped under 40. After a bright and breezy 55, a century on day four would do his future prospects no harm and set up this match nicely.
SHOT OF THE DAY: Late in the day, Bell strolls down the pitch to Harris and lofts the bowler high over long-on for a maximum.
STAT OF THE DAY: The last 34 centuries by England openers have all been by left-handers. Michael Vaughan's ton versus West Indies in 2004 was the last by a righty.
USER COMMENT OF THE DAY: "I think Dale Steyn's bowling action is being affected by the huge moustache he has hanging on his upper lip, my little boy of 14 months has a moustache the same," Gavin on the Gary Neville of international cricket.
- Alastair Cook