Serhiy Tihipko, who came from nowhere to third in the first round of this year's presidential elections, would have comfortably beaten both Yanukovych or Tymoshenko in the final round had he come second, according to an exit poll in which over 20 thousand voters were questioned - he would be the new president. [It could well be that president Yushchenko's appeal to his supporters to vote 'against all' and perhaps his granting of Hero of Ukraine status to Stepan Bandera may have cost Tymoshenko the top job.]
While Tihipko remains popular Party of Regions will definitely not want any early parliamentary elections for fear of losing seats to his political project- a situation that gives the NUNS bloc in the current VR huge leverage. NUNS themselves could be wiped out in any early elections also. Party of Regions cannot form a majority coalition and evict the current Tymoshenko-led cabinet with any other party's participation [except of course BYuT, but this is hardly likely]. The support of the remaining two parliamentary VR parties is insufficient.
Some observers consider that Tymoshenko, by challenging the results of Sunday's poll through the courts, is merely playing for time in order to come to an arrangement with Yanukovych whereby he obtains his favoured selections for head of the SBU and Prosecutor General [via parliament] while she remains head of government, perhaps even with some PoR members filling empty chairs in the cabinet, until after this summer's recesss. To throw in the towel right away would be perceived as weakness by her supporters and opponents alike and would reduce the possibility that she remains PM. But, as in 2004, everyone knows who the next president of Ukraine will be...
p.s. If Tihipko had endorsed Tymoshenko after the first round in exchange for her firm offer to appoint him PM in the event of her victory, more than likely they both would be sitting in the top two posts in the country. Tihipko may be regretting not taking up Tymoshenko's offer - he would have been in control of the country's government now... as it is: "He goes away with nothing.."