Selection is likely to be South Africa's biggest challenge ahead of their one-off day-night Test against Zimbabwe, starting at St George's Park on Tuesday.

Zimbabwe are unlikely to stretch the home side but South Africa, ranked second in Test cricket, will want to establish their best XI in this four-day Test ahead of a three-match series against India, starting in Cape Town on January 5.

With the return of AB de Villiers and Dale Steyn after long absences from Test cricket, and with all South Africa's front-line fast bowlers fit for the first time in more than a year, coach Ottis Gibson described the selection issue as "a good nightmare".

"India are the number one team in the world at the moment and we know we need to be at our best if we are going to compete with them and beat them, which is our ultimate goal," said Gibson.

Six or seven batsmen? Three or four fast bowlers? A spin bowler? An all-rounder? These are all questions that will be troubling Gibson and his fellow selectors.

The situation is complicated by South Africa’s unique racial balancing act, with Cricket South Africa committed to having an average of six players of colour, including two black Africans, in their starting teams.

Three black Africans – batsman Temba Bavuma, all-rounder Andile Phehlukwayo and fast bowler Kagiso Rabada – played in South Africa’s most recent Test matches, two one-sided encounters against Bangladesh.

But with batsman De Villiers and fast bowlers Steyn, Vernon Philander and Morne Morkel back in the mix, only Rabada of the three seems guaranteed to start in what should be another lop-sided contest.

Assuming captain Faf du Plessis is passed fit after recovering from shoulder surgery, it will be difficult to fit Bavuma into the batting line-up, while Phehlukwayo's medium-pace is unlikely to be required when there are four world-class fast bowlers in the squad.

Zimbabwe had a disappointing warm-up when they were beaten by a largely unheralded Invitation team in Paarl, but they were able to gain some experience with a pink ball under floodlights.

It is the first day-night Test to be played in South Africa. When the hosts held their first practice under lights on Friday they found the ball helped the seam bowlers more at night than during the day, which has been a pattern in floodlit Tests elsewhere.

The floodlights at St George's Park were upgraded during the off-season. Only two Twenty20 matches have been played at the ground since then, with the team batting second winning on both occasions.

Squads:

South Africa: Faf du Plessis (capt), Dean Elgar, Aiden Markram, Hashim Amla, AB de Villiers, Temba Bavuma, Quinton de Kock (wkt), Theunis de Bruyn, Andile Phehlukwayo, Vernon Philander, Keshav Maharaj, Kagiso Rabada, Dale Steyn, Morne Morkel, Duanne Olivier.

Zimbabwe: Graeme Cremer (capt), Hamilton Masakadza, Solomon Mire, Craig Ervine, Brendan Taylor, Sikandar Raza, Chamu Chibhabha, Ryan Burl, Peter Moor, Regis Chakabva (wkt), Kyle Jarvis, Chris Mpofu, Tendai Chatara, Blessing Muzarabani, Tendai Chisoro.