A German government that does not include Chancellor Angela Merkel’s party after September’s general election appears more likely after two defeats in key regional votes.

And a mooted contender to succeed Mrs Merkel who is not seeking a fifth term as Chancellor in the autumn, has said the centre-right needs to raise its game to keep the country’s top job.

Final results showed that Mrs Merkel’s Christian Democratic Union (CDU) was defeated in Sunday’s elections by two popular incumbent state governors. The Greens’ Winfried Kretschmann won in Baden-Wuerttemberg and the centre-left Social Democrats’ Malu Dreyer was victorious in Rhineland-Palatinate.

While the CDU always faced an uphill battle against the pair, the results were painful. It lost the two states – both of which were once strongholds, but have long since slipped from its grasp – by about eight percentage points. It won 24.1% of the vote in Baden-Wuerttemberg and 27.7% in Rhineland-Palatinate, its worst showing in both states since the Second World War.

Mrs Merkel’s federal government faces discontent over a slow start to Germany’s coronavirus vaccination drive, while most restrictions remain in place and infections are rising again. And her centre-right bloc has been hit over the past two weeks by allegations that a few MPs profited from deals to procure masks early in the coronavirus pandemic.

In both states that voted on Sunday, the results make three-way coalitions between the Greens, Social Democrats and pro-business Free Democrats possible – highlighting the possibility, though it has seemed a long-shot so far, of such an alliance at national level.

So far, the Union bloc of Mrs Merkel’s CDU and Bavaria’s Christian Social Union (CSU) leads polls by a distance from the Greens and Social Democrats, despite softening support. But it cannot count on a popular incumbent in the September 26 election for the new German parliament, since Mrs Merkel is stepping down after nearly 16 years in power.

CSU leader Markus Soeder, the governor of Bavaria and one of two serious contenders to be the centre-right candidate to replace Mrs Merkel, described the results as a “wake-up call”.

Mr Soeder said: “One thing is clear since yesterday evening: theoretically, there are majorities beyond the Union. So the belief or hope that 1 or 2% more or less doesn’t matter, that the Union will have the chancellor in any case, is no longer 100% certain since yesterday evening.”

He added: “That means we won’t be able to get through the federal election in September in the sleeping car. We need a clear direction, a clear strategy.”

He called for vaccinations to be accelerated and for the centre-right “to line ourselves up more broadly than just with corona”.

Sunday’s results are not helpful for new CDU leader Armin Laschet, the governor of North Rhine-Westphalia state, who was elected in January. He has said that he and Mr Soeder, who has not officially declared his ambitions, plan to make a decision in April or May on who will seek the chancellorship.

The state elections gave the environmentalist and traditionally left-leaning Greens new confidence for the national election campaign, in which they are expected to make their first bid for the chancellery. Co-leader Annalena Baerbock said a decision on the candidate will be made “in the coming weeks.”

The Greens’ general secretary, Michael Kellner, noted that this is the first time since West Germany’s first election in 1949 that there is no incumbent seeking re-election. “The race is open and that gives us a huge opportunity,” he told ARD television.

The elections gave some comfort to the Social Democrats, who have been struggling with dismal federal poll ratings.

The Social Democrats’ candidate for chancellor, finance minister Olaf Scholz, said the results showed that “forming a government is possible without the CDU”.

One party that did not benefit from discontent was the far-right Alternative for Germany which has opposed coronavirus restrictions and is in a court stand-off with the domestic intelligence agency over whether it can be put under observation as a “suspected case” of right-wing extremism.

The party lost about a third of its support compared with strong showings in 2016, taking 9.7% of the vote in Baden-Wuerttemberg and 8.3% in Rhineland-Palatinate.