Gaining Mugabe's endorsement will also be crucial. After all, the long-time president still dominates the party, and through ZANU-PF history Mugabe's hand has been central in ensuring the rise or fall of various politicians.
Looking to his successor, Mugabe's will presumably want a leader that can keep the party together, but crucially also one who will allow him to continue playing a part in politics from behind the scenes. The person who seems to fit this bill closest is the figure who has long been considered Mugabe's blue-eyed boy, Mnangagwa, and there have been signs that he is indeed Mugabe's preferred candidate.
For example, when Mugabe held a press conference on the eve of the July 2013 election, he was flanked by the press secretary on one side and Mnangagwa on the other. Asked if Mnangagwa's presence meant he was next in line to the throne, Mugabe seemed to be caught off guard and hastily claimed the then defence minister had just dropped by for a visit. In more concrete terms, however, it is notable that Mugabe has always assigned important government ministries to Mnangagwa - including state security, home affairs, defence and justice - and that Mnangagwa is believed to be one of just a few ZANU-PF officials allowed to maintain direct and close ties to Zimbabwe's security community, a privilege not understood to be granted to Mujuru.
It is possible Mugabe considers Mujuru more of a lightweight than the hard-line Mnangagwa and may believe she will struggle to deal with the opposition, foreign interests, and the party's internal tensions. He may also be concerned that ZANU-PF's image of being a fearless revolutionary party will be lost under Mujuru.
In fact, Mugabe's ties to Mujuru have always been somewhat opportunistic, with the president arguably maintaining close links with her to appease Solomon Mujuru, Joice's powerful late husband.
Team Mnangagwa vs. Team Mujuru
Nevertheless, Mugabe has yet to explicitly name his preferred successor, and over the coming year, a political civil war is likely to wage between the two hopefuls. In this fight, Mujuru may have won the provincial election battle, but Mnangagwa arguably has behind him the country's most canny strategists with the experience and vision to devise an overall victory. The most notable of these are Jonathan Moyo and Patrick Chinamasa, a formidable duo that helped deliver various electoral victories for Mugabe, though Mnangagwa also has the support of other senior ZANU-PF figures who could prove useful.
By contrast, Mujuru's faction looks weaker. The most conspicuous politician in her faction is probably Didymus Mutasa, a politburo member who many believe constitutes little threat, while the same could be said of ZANU-PF spokesperson Rugare Gumbo, another figure believed to be loyal to Mujuru.
A joint presidency?
How things will pan out over 2014 and which candidate finally achieves their long-held ambition of becoming the next presidential nominee remains to be seen. All eyes are on the party congress in December.
However, in many ways, whatever happens at that conference will not be the end of the story, but just the latest chapter in the Mujuru-Mnangagwa rivalry. Indeed, it is highly improbable that a single person will dominate the party as Mugabe has, and whichever faction wins will have to ensure the other faction does not feel like it lost too badly.
After all, if Mujuru takes over ZANU-PF, she will not only have to appease Mnangagwa's ambitious allies for the sake of unity, but also probably concede considerable power in order to secure the electoral experience of his faction with the 2018 general elections in sight.
On the other hand, if Mnangagwa emerges victorious, he too will have to be generous to Mujuru's faction in order to retain the support of the party's lower ranks, the vice-president's power base, in the same interests of cohesion and electoral success.
Thus, whichever group triumphs, it is unlikely to drive the other into obscurity. It is more likely that the two leaders will share power to a large degree, at least in the short-term, resulting in a dual power regime within the party, with the leadership role itself being largely nominal. It seems the political tale of Mujuru vs. Mnangagwa is destined to drag on for quite some time yet.
Simukai Tinhu is a political and economic analyst with an academic background in African politics (University of Cambridge). He is the Editor of Maximum Africa Journal, a weekly African affairs magazine. Follow him on twitter @STinhu