BERLIN -- Armin Laschet, the governor of Germany's most populous state, emerged victorious Tuesday from a bruising power struggle and became the candidate of Angela Merkel's centre-right bloc to succeed the longtime chancellor in the country's September election.

Laschet, 60, now faces another big battle: to connect with voters and win over frustrated fellow conservatives who backed his more popular rival, Markus Soeder.

Their Union bloc was the last major political force to nominate a candidate for chancellor in the Sept. 26 parliamentary election. Merkel isn't seeking a fifth term after nearly 16 years in power.

The race turned into a heated duel after both Laschet, the leader of Merkel's Christian Democratic Union, and Soeder, who leads its smaller Bavarian sister party, the Christian Social Union, declared their interest in succeeding Merkel.

"The die is cast: Armin Laschet will be the chancellor candidate of the Union," Soeder said Tuesday, conceding after the CDU leadership backed Laschet in a late-night vote. "Only a united Union can be successful," he added.

"We will support him without a grudge, with all our strength," he told reporters in Munich.

Parts of the CDU strongly favoured Soeder, while others vehemently opposed his bid to elbow Laschet aside for the top job. Soeder has much better poll ratings, but Laschet was elected in January to lead by far the bigger of the sister parties. It was primarily a conflict of personality and style rather than policy.

Laschet is the governor of the western state of North Rhine-Westphalia. Soeder is the governor of Bavaria.

Early last week, Laschet informally rallied the CDU leadership behind his bid. But Soeder said the matter shouldn't be resolved "only in a small back room."

After days of talks failed to produce a solution but laid bare deep divisions in the CDU, Soeder said Monday that the bigger party must decide the matter and he would respect a "clear decision."

At a turbulent CDU leadership meeting, 31 of its members voted for Laschet, nine for Soeder and six abstained, news agency dpa reported. That prompted Soeder to concede.

The Union bloc campaigns together in federal elections and has a joint parliamentary group in Berlin. The CSU exists only in Bavaria, while the CDU runs in Germany's other 15 states.

The Union leads polls ahead of the environmentalist Greens, who on Monday nominated Annalena Baerbock as their first candidate to be chancellor. The struggling centre-left Social Democrats nominated Finance Minister Olaf Scholz as their candidate months ago.

Laschet, a miner's son from Aachen, a city on Germany's border with Belgium and the Netherlands, served as a member of the European Parliament from 1999 to 2005.

He was elected in 2017 as governor of North Rhine-Westphalia, a traditional centre-left stronghold.

Supporters frequently point to that victory when asked about his poor poll ratings -- along with his success in the race to lead Merkel's party, in which he beat conservative favourite Friedrich Merz.

They also emphasize his conciliatory nature. Laschet governs his home region in a coalition with the pro-business Free Democrats, the CDU's traditional ally, but likely could work smoothly with a partner further to the left. Current polls suggest the Greens could hold the key to forming the next government, even if Baerbock doesn't win the chancellery.

Still, Laschet hasn't had a honeymoon as CDU leader. In recent weeks, he drew criticism for appearing to dither over how to manage a resurgence in coronavirus cases, while Soeder has cultivated an image as a decisive backer of tough action. Last month, the CDU lost two state elections.

National polls have shown the Union giving up gains it made on the strength of Merkel's management of the early stages of the pandemic. There has been discontent with a slow start to Germany's vaccination campaign and a scandal over some Union lawmakers' alleged profiteering from mask-procurement deals last year.