BERLIN - German Chancellor Angela Merkel launched a final week of campaigning with the wind at her back Monday but a debacle for her junior partner in a Bavarian state poll spelled potential trouble.
While Merkel's allies captured nearly one vote in two in the wealthy southern state Sunday, their coalition partners in Bavaria and at the national level, the Free Democrats, crashed out of the regional parliament.
Analysts said the result made a third term for Merkel look increasing likely in next Sunday's general election.
But it raised the prospect of a nail-biter finish to see whether she can continue her centre-right government or will have to form a "grand coalition" with the rival Social Democrats.
"I'd say the odds are 50-50 for a grand coalition - it's really the only possible option if the current government is not re-elected," Klaus-Peter Schoeppner, head of the independent polling institute Emnid, told AFP.
After what many have called a lacklustre election season, the top-selling daily Bild summed it up: "The final week of the federal campaign will be thrilling."
In Bavaria, the conservative ruling Christian Social Union captured an absolute majority of seats in parliament with nearly 48 percent of the vote. Its substantial victory means it can drop the FDP and govern alone.
"That is a huge vote of confidence," incumbent state premier Horst Seehofer told cheering supporters.
Merkel campaigned hard in the state's world-famous beer tents, pointing out that a big Bavarian win would lend momentum to her re-election bid at the helm of Europe's top economic power.
National polls give Merkel's conservatives an around 13-point lead over the main opposition Social Democrats (SPD), who scored just over 20 percent in Bavaria, historically a conservative state.
Merkel's chief election rival, Peer Steinbrueck of the SPD, took heart from the Free Democrats' catastrophe.
"This is the 13th state election in a row in which the centre-right love match failed to win," he told public television.
"There is a good chance that this will also happen on the federal level in a week's time."
The ecologist Greens turned in a dismal 8.6 percent, in keeping with a downward trend on the national level.
FDP leader Philipp Roesler called his party's three-percent result a "bitter defeat".
"But it shows now is the time to fight, dear friends," he said to applause from supporters in Berlin.
"This is a wake-up call for all liberals in Germany."
Commentators said the poor showing in Bavaria by the Free Democrats could in fact give them a boost in the September 22 general election.
Voters who would like to see the Merkel alliance continue and who are concerned about the FDP's disaster in Bavaria might give votes to the party, dragging on the conservatives' own score.
"The FDP will now bank on a pity effect and votes from the conservatives," news weekly Die Zeit said on its website.
That prospect led many Christian Democrats to warn against ceding votes to the FDP.
"The FDP will be fine on its own - stay cool, don't give away our votes," federal Environment Minister Peter Altmaier wrote on Twitter.
Germany's 62 million voters make two checks on their ballots in the national election - one for a candidate and one for a party - allowing the option of splitting their support.
It is that type of tactical voting that the FDP is counting on next Sunday, its general secretary Patrick Doering told public television Monday.
Merkel led a left-right grand coalition during her first four-year term. At the last election in 2009, a thumping 14.6-percent result for the FDP allowed Merkel to form a government with the conservatives' traditional allies.
But this time, political scientist Oskar Niedermayer of Berlin's Free University warned, "It is going to be very tight for black-yellow," on rolling news channel NTV, referring to the colours of the current coalition.