Martin Schulz at the SPD gathering in Vilshofen | Sebastian Widmann/EPA Martin Schulz puts fire (and beer) in Social Democrat bellies Center-left candidate avoids confrontation with Merkel but calls out Trump for taking ‘ax’ to democracy.

VILSHOFEN, Germany — If the warm-up band says anything about the quality of the main act, Martin Schulz had a good gig Wednesday when Austrian Chancellor Christian Kern predicted that the German centre-left's candidate will "burn brighter and blaze higher" in elections this fall.

Presenting himself as the "backing band" for the German Social Democrats' (SPD) candidate to replace Angela Merkel as chancellor, Kern said the SPD's spike in popularity since it named Schulz candidate was "no flash in the pan."

"Political change is within reach after a phase of not so much optimism," Kern told a crowd of about 5,000 SPD supporters gathered in the Bavarian town of Vilshofen for "Political Ash Wednesday," a German tradition where party leaders rally the faithful in beer tents.

“The SPD wants to become the strongest political force of the Federal Republic of Germany," Schulz told the crowd. "And I want to become chancellor.”

In the four weeks since it selected the former president of the European Parliament as its candidate, the SPD has shot ahead in opinion polls and even overtaken Merkel's Christian Democrats (CDU) and their Bavarian allies in some surveys. The party, which has twice served as junior partner in a Merkel-led 'grand coalition,' has surged more than 10 percentage points and was seen winning 32 percent of votes in the latest INSA poll in Bild.

Schulz won applause for saying he had "political competitors, not foes — not even in a beer tent."

Schulz avoided head-on attacks on Merkel, whom he referred to in Wednesday's event only as "the CDU chairwoman" — though he did have harsh words for her Bavarian ally Horst Seehofer, who was attending a similar beer-tent rally of his conservative Christian Social Union (CSU) just down the Danube from the SPD event.

Schulz saved most of his criticism for Donald Trump, saying the new U.S. president had taken an "ax to the roots of democracy." In a similar vein, he told Turkish President Recep Tayyip Erdoğan to focus on the rule of law in Turkey rather than campaigning for support among Turks living in Germany.

Playing to his genial image, Schulz won applause for saying he had "political competitors, not foes — not even in a beer tent" and he played to the SPD's traditional strength as a defender of a fairer society.

The Ash Wednesday rally gave a preview of the next phase of Schulz's campaign: having saved the party from depression, he now wants to convince the German voter that their country will be in good hands if he takes over from Merkel.

The SPD will officially anoint him as their candidate and party chairman on March 19 in Berlin. With the elections scheduled for September 24, nearly seven months away, Schulz wanted time to meet ordinary Germans — and perhaps re-connect with domestic politics after more than two decades in the European Parliament — before setting out the markers for the campaign.

Deploying home-spun rhetorical skills that are more folksy and anecdotal than Merkel's, the SPD candidate talked about the struggle to make ends meet even for dual-income families, and elderly workers' fear of losing their jobs.

The event was a shot in the arm for the struggling Bavarian branch of the SPD, which is so divided that it currently has six candidates competing to run the party in the state. The rally appeared to have attracted a bigger crowd than the more traditional CSU Ash Wednesday event 20 km away in Passau, which has a maximum crowd capacity of 4,000. This year's SPD event had 30 additional meters of seats in the beer tents than last year, to seat 5,000.