Biden, facing a political crisis as Democrats question the viability of his campaign, is minutes away from holding his first solo press conference of the year -- and since the debate two weeks ago.

It's an opportunity for Biden to change the narrative after his poor performance that night triggered a drumbeat of concerns in his own party that he might be too weakened to win against Donald Trump this November.

But any stumbles in the unscripted setting will only add fuel to the fire, despite Biden's repeated attempts to rebuff his critics and his insistence that he is staying in the race.

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German Chancellor Olaf Scholz addressed Biden's viability and future during an interview Thursday on the PBS NewsHour, saying, "it would be a big mistake to underestimate the president."

"I just can tell you from my perspective, as someone that is speaking with Biden, he is very focused and he is very, intensely doing what the president of the United States has to do for leading [NATO]," Scholz said.

Scholz said that had not seen moments in his most recent interactions with Biden that indicated the president is not up for another four years.

-ABC News' Benjamin Siegel and Will Gretsky

Biden introduced Ukraine's President Volodymyr Zelenskyy as President Putin at a meeting about the Ukraine Compact at the NATO summit Thursday evening.

Biden quickly corrected himself, saying that he was "so focused on beating Putin."

Zelenskyy laughed off the gaffe.

"I'm better," Zelenskyy said.

"You are a hell of a lot better," Biden replied.

The exchange came shortly before Biden was scheduled to hold his first solo news conference since the presidential debate.

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Biden introduces Zelenskyy as Putin in gaffe during NATO summit meeting

President Joe Biden accidentally called Ukrainian President Volodymyr Zelenskyy by the name of his rival, President Vladimir Putin, when introducing him at the NATO summit.

-ABC News' Michelle Stoddart