Joe Root believes captain Alastair Cook is the key to England beating South Africa away for the first time in over a decade.
Both batsmen limbered up for the four-Test series by posting impressive centuries on the penultimate day of their warm-up match against South Africa A, and look in good order ahead of the Boxing Day opener.
South Africa, who last lost a home series to England in 2004-05, will hardly have needed a reminder about the pair's class, with Cook standing as the top Test run-scorer in 2015 and Root sitting second.
And for Root, runs for Cook equal results for England.
"When he scores runs we do well, that's as simple as it is," said Root after England ended day two in Pietermaritzburg 243 ahead.
"He leads from the front, he's had a fantastic year as a batter and as a captain and hopefully he can continue.
"You want him out there as long as you can. I know he's got a sore back but it's what he does, he bats hours and hours on end."
Root was happy to see Alex Hales register a maiden first-class 50 in England colours.
The uncapped Nottinghamshire batsman will make his Test debut in Durban.
"I thought he played extremely well," added Root.
"It took some real high skill to get through some tough conditions."