Woakes confirmed to replace injured Anderson
Cook backed Woakes to prove how much he has developed as a cricketer. While accepting the loss of Anderson was "huge," Cook said that Woakes's selection would strengthen the batting and that he had shown he was well equipped to deal with the pressure of international cricket.
"He's ready to go now," Cook said. "He's learned his trade and it's about him delivering now on the big stage for England.
"He can do it. I know it a Twenty20 game, but that 40-odd he got in Sharjah under pressure to see his side home... he does it for Warwickshire a lot. He's desperate to be given opportunities.
"It's been quite hard for him to get in the side because of the way that Jimmy Anderson and Stuart Broad have remained so fit and how long they've been around. This is a great opportunity and he's a really good cricketer."
Hales, meanwhile, is set to become Cook's eighth opening partner in Tests since the retirement of Andrew Strauss after the 2012 series against South Africa. Instead of letting the occasion get to him, Cook has urged Hales to play his natural game as England seek to achieve "something very special" in the coming weeks.
Hales had impressed as a limited-overs opening batsman but, after starting the 2015 County Championship with some high scores, he convinced the selectors that he had the skills required for the longer format. Hales made 236 against Yorkshire, the champions, in April, and hit 141 against Hampshire a week later. Another big century in August - 189 against Warwickshire - reiterated that he was ready for Tests.
"It's absolutely vital he plays the way he plays for Nottinghamshire," Cook said. "One of the biggest mistakes you can do as an international player is to think you have to play a different way.
"The reason he got selected was for the way he plays and the big hundreds when he gets in. Certainly at the start of last year, that made everyone sit up and take notice of him. You can't change the way he plays, he's just got to be true to himself and that will be good enough."
Cook also suggested that the selectors will show some patience with Hales in the knowledge that he makes his debut against a top-quality seam attack and that it may take time to find his feet at this level. Adam Lyth and Sam Robson were given seven Tests when they had an opportunity to open with Cook. Both batsmen made centuries in their second Tests to ensure they won an extended run.
"Always at the top of the order against the new ball and world-class attacks, you're going to have low scores," Cook said. "So it's about how you handle that and, when you're in, make sure you cash in and go big to compensate.
"Alex isn't really under pressure. No more than myself or any of the guys; that's what happens when you play Test cricket.
"When you're picked to make your debut for England it's a great five days. It's a culmination of a lot of hard work not just by yourself but all the commitment the family have made, the coaches, your friends...it's a big occasion for a huge number of people.
"But he's ready to play. He's earned his selection and been around the squad in the UAE. He knows what it's about, he's got a T20 international hundred and an ODI hundred. He can certainly play and I hope he's looking forward to the challenge, showing people what he can do rather than just being another opener off the rank."
Cook also reflected on a remarkable year from a personal perspective. This time 12 months ago, he was reeling having been sacked from the England ODI captaincy. From a situation where he was looking forward to leading the side in the World Cup, he suddenly realised he would not be at the tournament.
Although he admitted that 2014 "wasn't a particularly fun Christmas," he has now accepted that the setback was a blessing in disguise and has allowed him the time and clarity of thought required to rediscover his best form in Test cricket. He goes into the final Test of the year having already scored more runs in a calendar year than any other England captain, and requiring 125 more to overtake the England record for a batsman (1,481), set by Michael Vaughan in 2002.
"In hindsight, it gave me two months to get away from the game," Cook said of the decision to relieve him of the ODI captaincy. "It gave me time to practice away from pressure for a period of time and I got to look at my Test-match game as a whole. Sometimes you do need to step out of the bubble and reassess what you need to do.
"And the benefit of that is that I scored a few runs this year. It's been good from a personal point of view. It wasn't a particularly fun Christmas last year but hopefully this year will be slightly different.
"South Africa are a good side. I don't know if this is a good time to play them: they're still ranked No. 1 in the world and they're tough to beat at home. You can't read too much into both sides' previous tours because conditions are so different. And always beware a wounded animal.
"The bookmakers make us underdogs but we were underdogs against Australia. And the conditions aren't too dissimilar to England. Playing four seamers and a spinner seems to have worked well for us and we're comfortable playing with that balance of the side. We could do something very special.
"But that's just talk isn't it? The guys are ready to test themselves against the best in their backyard. This side like being the underdogs and likes throwing a few punches."
George Dobell is a senior correspondent at ESPNcricinfo