Ahead of the meeting between the two heads of state, the US president expressed, in public at least, low expectations of his first face-to-face talks in a year with Chinese President Xi Jinping.

Before departing for San Francisco, asked about his yardstick for success, US President Joe Biden said, "To get back on a normal course of corresponding, being able to pick up the phone and talk to one another when there's another crisis".

Their four hours of talks having produced agreement on that and more, the US leader was notably more upbeat about the meeting afterward.

"I believe they were some of the most productive and constructive discussions we've had," he declared. That the two leaders exchanged views in an atmosphere of mutual respect has obviously been conducive to generating the buzz of positivity that both sides have exhibited after the talks.

Summarizing the significant progress that had been made in the two leaders' discussions that were "good, comprehensive and in-depth", Chinese Foreign Minister Wang Yi said that the summit would be seen as a milestone in the history of US relations.

Indeed, anyone worried about what has been a continuous downward spiral of the two countries will now be heaving a sigh of relief, as the constructive engagement the two leaders committed to should, if nothing else, arrest the deterioration in bilateral relations. So long, of course, as the US side holds true to the "tangible steps in the right direction" the talks have produced, something it found difficult to do?after their previous meeting in Bali because of the anti-China caucus in the US Congress.

In the absence of a joint statement, it remains to be seen how much the two sides' opinions converge on the Chinese president's proposal that the countries assume a "new vision" for their relationship based on them making the right choice of cooperation rather than confrontation.

Stating that it is unrealistic for either country to change or lay down the law for the other, Xi proposed the two countries build "five pillars" to support stable, healthy and sustainable relations. He proposed that the two sides jointly establish correct perceptions of each other, effectively manage their differences, promote mutually beneficial cooperation, assume their responsibilities as major countries, and promote people-to-people exchanges.

That there were perceptible agreements reached, such as the reinstatement of direct military-to-military communication, shows that building these pillars is doable. That was reinforced by the joint climate statement the two countries' climate negotiators issued on Tuesday, which has "added a driving force for the China-US relationship to stop falling and begin stabilizing", as Xinhua News Agency observed, and is heartening news ahead of the upcoming UN climate summit in Dubai later this month.

All in all, the summit as Wang Yi said, can have far-reaching influence as the two leaders put forward guiding opinions on the most prominent issues in bilateral relations and set out the future-oriented direction for the two countries to get along.