"We're tied together like mountain climbers on the same rope," she says in an interview with the Financial Times.
The perilous image is apt. Popular support for Mr Yushchenko, the country's pro-western, reformist president, has fallen steadily since he took power, as a result of a sluggish economy, cautious reforms, continuing corruption and worries about worsening relations with Russia.
Mr Yushchenko's party, Our Ukraine, is struggling, with 16 per cent support. The conservative, pro-Russian Regions party, led by Viktor Yanukovich, a former prime minister who lost to Mr Yushchenko in last year's presidential election, is well in the lead with 28 per cent support.
Our Ukraine's and Mr Yushchenko's hopes of victory depend largely on his potential coalition partners - most notably Ms Tymoshenko, whom he sacked just three months ago, and Vitali Klitschko, the recently retired champion boxer who is heading one of five "Orange" groups in the elections.
Ms Tymoshenko says she worries that Mr Yushchenko may be waking up to his predicament too late.
"After our victory [last year], everyone thought the war was won. All the political battalions that took part deflated like balloons, be-came apathetic, weak, less effective. It scares me," she says.
"It seems to me our whole Orange team, including the president, underestimates the colossal risk of a revanche."
During the past three months Mr Yushchenko had flirted with the idea of forming a coalition with the centrist speaker of parliament, Volodymyr Lytvyn, or even with Mr Yanukovich. But such talk only further dismayed the president's supporters.
Now Mr Yushchenko has returned to his old base, hoping that after the March vote he can cobble back together roughly the same coalition of parties that backed him last year.
Nevertheless, there is an intense rivalry between the Yulia Tymoshenko Bloc, which has 15 per cent of voter support, and Mr Yushchenko's Our Ukraine.
Delicate issues - such as who would be prime minister in their coalition - are being put off until after the vote.
Ms Tymoshenko continually criticises Yuri Yekhanurov, her successor as prime minister, who is far less outspoken and far more cautious about economic and bureaucratic reforms than she was.
Mr Yushchenko has said he would like to keep Mr Yekhanurov as premier after the elections on March 26 but Ms Tymoshenko wants the job back if her bloc beats Our Ukraine at the polls.
Meanwhile, Mr Klitschko, a former world heavyweight champion who is one of the country's most popular athletes, has come to the president's aid.
The boxer will lead the electoral list of candidates for a bloc of two parties aligned with Our Ukraine. Mr Klitschko has hinted he will also run for mayor of Kiev in simultaneous local elections.
Should Mr Yushchenko manage to hold on to power, however, his influence will be curtailed. Changes to the country's constitution, hammered out in a compromise with the preceding, pro-Russian government, will weaken presidential powers and strengthen those of parliament.
Source: Financial Times