South Africa kept their series hopes alive by beating Sri Lanka in the third one-day international in Pallekele, but remain under pressure at 2-1 down and have to win the next game to avoid a series defeat.
The teams will square off once more at the same Pallekele ground before heading back to Colombo for the fifth and final match.
Winning the toss will again be crucial since the team batting first has won every game on this tour, including the warm up. The toss may be an uncontrollable factor, but even if South Africa do not get the chance to bat first, they should have more confidence after their batting performance on Friday.
David Miller was the man of the moment for the Proteas and his unbeaten 85 enabled his side to post a competitive total. Miller was pretty pleased with the way he performed.
His effort even drew congratulations from South Africa paceman Dale Steyn, currently in America filming a movie with Adam Sandler.
The bad news is that South Africa are likely still to be without Hashim Amla. The Proteas' star batsman remains in doubt after suffering an on-field injury in the second ODI. He did manage a nets session on Saturday, but a call on his fitness will only be made on the morning of the game.
If he is not entirely fit, it's unlikely that Amla will be risked as South Africa will be keeping one eye on their Test series against Pakistan later this year.
Winning in Sri Lanka is a tough challenge for any team. Many have tried and failed and the relatively young and inexperienced South Africa outfit have done well to register a victory. The hosts have a side packed with experience, and even under a young captain they have produced some clinical performances.
South Africa's biggest weakness is almost certainly their lack of a proven spinner at this level, which is not something Sri Lanka are troubled by.
If the weather holds up and South Africa bat first, it should be another entertaining contest. But if Sri Lanka take to the crease first, it could well be curtains for the Proteas' series prospects.