"It's much too early," Biden said, calling himself "a great respecter of fate."
Surveying the state of the world's largest economy, Biden was optimistic.
He declared the Covid-19 pandemic in the United States "over" and predicted that his administration would tame inflation -- the main reason for his weak approval ratings and the reason Republicans believe they can take control of Congress in the upcoming November midterms.
"We're going to get control of inflation," he said.
Troops to Taiwan?
In another surprise moment, Biden once again appeared to challenge decades of US policy on Taiwan with a vow that he would send troops to defend the self-ruled island if China tried to invade.
"Yes," he said, adding that this would happen if there was "an unprecedented attack" -- possibly referring to something beyond the frequent saber rattling conducted by Chinese military forces around Taiwan.
While Washington does arm Taiwan, it has long maintained a policy of "strategic ambiguity" on whether it would intervene militarily if Beijing were to invade. The policy is designed to dissuade both China from invading and Taiwan from formally declaring independence.
The White House said that Biden's latest remarks did not indicate a change but Beijing condemned the comments on Monday during a daily foreign ministry press briefing.
"The US remarks... severely violate the important commitment the US made not to support Taiwan independence, and sends a seriously erroneous signal to Taiwanese separatist independence forces," spokesperson Mao Ning said.
However, Taiwan's Ministry of Foreign Affairs expressed its "sincere gratitude" for Biden's support.
"In the face of China's military expansion and provocative actions, our government will continue to strengthen self-defence capabilities to firmly resist the expansion and aggression of authoritarianism, and at the same time deepen the close Taiwan-US security partnership," the ministry said in a statement.
'Consequential' nuclear response
In another tough message to the United States' biggest economic and geopolitical rival, Biden said he had warned president Xi Jinping not to support Russia militarily in its invasion of Ukraine.
He said he told Xi that US and other foreign investment in China would be disrupted and to think otherwise would be "a gigantic mistake."
He also said that if Russian president Vladimir Putin uses nuclear or other non-conventional weapons against Ukraine the US response will be "consequential."
When asked what he would tell Putin if the Russian leader was mulling such a move, he said: "Don't. Don't. Don't."
Biden praised the Ukrainians for their gritty fight against the huge Russian invasion and said "they're defeating Russia."
Asked how to define victory for Kyiv, he said "winning the war in Ukraine is to get Russia out of Ukraine completely."
But given the scale of human suffering and destruction inflicted in resisting the Russian onslaught, "it's awful hard to count that as winning," he added.
'More to give'
Despite his poor ratings and polls showing Democrats likely to lose control of at least one chamber of Congress, Biden said he is upbeat.
Noting that employment is booming and the economy is strong, Biden said "we hope we can have, as they say, a soft landing."
On whether at his age he is physically and mentally able to continue in the gruelling job, Biden said: "watch me."
"It's a matter of, you know, that old expression -- 'the proof of the pudding is in the eating.'"
When asked his source of inspiration when times get tough, Biden mentioned his son Beau who died in 2015 but also his parents' exhortation to "just get up."
Biden said he had "a lot more to give."