This, South Africa think, is their best ODI XI. On the early evidence of their performance in Johannesburg, you might agree. Four of the top five scored half-centuries, two of those at a strike rate above 160. They had two century stands, and an overall run-rate that was consistently close to seven. Having asked Pakistan to pull off their highest successful chase, the quicks applied pressure and made enough early breakthroughs to swing the advantage their way inside 20 overs of the opposition's reply.

But in the last quarter of the match, they very nearly lost their way. With only five frontline bowlers, South Africa did not seem to have enough options to stop Fakhar Zaman. Tabraiz Shamsi was particularly expensive and probably should not have bowled his final spell, especially as Lungi Ngidi had an over in hand. Pressure, as it so often has in the past, threatened to take over but Andile Phehlulwayo held his nerve in the penultimate over, leaving Ngidi to defend 31 off the 50th. Off the first ball, Aiden Markram fired in a strong throw, Quinton de Kock's gestures led Zaman to believe the ball was heading to the non-striker's end when it was actually heading to him and Fakhar was run out, all but guaranteeing South Africa their first points on the World Cup Super League.

They have those now, and remain in contention to win just their third trophy in nine series under Mark Boucher, but we all know one victory doesn't make a summer and this one won't make South Africa's. All it does is give them an indication of what they can do when most parts of their game are working, just in time for this combination to be separated ahead of the decider. Almost half the XI will leave after this match for the IPL.

The debates around the squad splinterting are multi-layered, not least because Pakistan have sent a full-strength playing group to South Africa in a pandemic and one argument is that the least the hosts could do is present their strongest side too.

The reality is that Cricket South Africa (CSA) cannot afford to do anything else. Apart from the fact that the CSA and the BCCI have an agreement that the April-May window will be kept empty for the IPL, CSA's Rands are no match for the IPL's dollars and the contracted players would prefer to earn the latter. The next question will be whether this series could have been played at another time but in a calendar affected by Covid-19 postponements and rearrangements that is unlikely, so this is what South Africa have to deal with.

"I wouldn't say I am nervous," the captain Temba Bavuma said. "We'll go into the (final) game wanting to win the game and fortunate or unfortunate that we don't have our main players available, the IPL boys. At the same time there is an opportunity for the guys on the fringes to really make a play for the team."

Let's start by looking at the players South Africa won't be able to call on. At the top of the order, they'll be without de Kock, who didn't look entirely at ease in the middle, but managed an assertive 80, came alive in the field, was often seen in conversation with Bavuma and played his part in the crucial run-out. They also won't have David Miller, who Bavuma said is "hitting the ball as well as he has in quite a while," and who contributed two aggressive half-centuries in the series, including his fastest, off 27 balls today.

Perhaps most importantly, their first-choice pace pack of Kagiso Rabada, Lungi Ngidi and Anrich Nortje are all India-bound, leaving South Africa light on attack. As you may expect, that will test their depth. Replacements include Lutho Sipamla, Beuran Hendricks, Junior Dala, Daryn Dupavillon, Lizaad Williams, and Sisanda Magala who bring a selection of skills including control, variation and speed but have just 13 ODI caps between them.

It will also ask questions of their team balance. In these two matches, South Africa opted for only five bowlers, which does not accommodate for the possibility that one of them could have an off-day. Today that was Shamsi. The only alternative option was Markram's offspin which was used earlier in the innings and there is no doubt South Africa will want a more threatening alternative. The IPL exits present the option for an allrounder such as Wiaan Mulder or George Linde to be considered, which could also change the length of the line-up. Currently, Phehlukwayo is in at No.7 but South Africa may prefer to move him one down and include a second two-in-one player.

At least South Africa will be able to keep the bulk of the batting lineup, including those who have found form such as Rassie van der Dussen and Temba Bavuma. Van der Dussen followed up his maiden hundred with a carefree 60 off 37 balls, although he was dropped on 0 for the second innings in succession. Unlike at SuperSport Park, when van der Dussen had to drag South Africa to a competitive total from 55 for 4, at the Wanderers, he had to build on a base of 169 for 2. He took on the spinners and was particularly strong on the sweep and is exuding a confidence in himself that South Africa will want to continue. He'll want to avoid offering early chances, but won't complain that Pakistan aren't taking them.

South Africa will also have Bavuma, who would have been disappointed not to score his first hundred as captain. The pace at which he starts his innings could become a talking point, but he caught up quickly and played an array of attractive shots. Although not always known for it, Bavuma is an attacking player, who uses his feet well, punishes the short ball and drives beautifully.

What they need is for Markram to start emulating the senior pair, especially after he looked in sublime touch for his 39. Markram has been dismissed 15 times in his 26 ODI innings for scores between 20 and 49, so his conversion rate is a concern that South Africa will hope can be addressed before this series ends.

Janneman Malan is likely to partner Markram in de Kock's absence while Miller's departure opens up an opportunity for Heinrich Klaasen to bat higher and Kyle Verreynne to play. Klaasen had a good series against Australia last year and has not had much time in the middle in this series so far but can use the final match to make a strong case to claim a middle spot permanently.

The reality is that South Africa's best ODI XI is blurry as one victory suggests it should be. There are some personnel that are obvious keepers and some positions that are still up for grabs. Although Bavuma noted that "the batting effort was much better," than in the first ODI, he acknowledged that "it would have been nice to finish the game a lot more clinically today."

So their best XI, it seems, is yet to be decided.

Firdose Moonda is ESPNcricinfo's South Africa correspondent