Pentagon official Randall Schriver told reporters after the longer-than-expected 90-minute meeting that Mattis "repeated our desire for a durable relationship that is a stabilizing force in the overall relationship".
Secretary of Defense James Mattis and China's Defense Minister Wei Fenghe are set to meet this week after talks between the two were canceled at the end of last month. -China relationship was spilling over into the military arena.
"I think that all of us joining hands together, ASEAN allies and partners, and we affirm as we do so that no single nation can rewrite the worldwide rule to the road and expect all nations large and small to respect those rules", Mattis said during a meeting with his Japanese and South Korean counterparts, according to The Hill.
In a recent reminder of the risks amid rising tensions, the Pentagon this month accused China of an unsafe and unprofessional manoeuver in the South China Sea that brought a Chinese ship dangerously close to a U.S. Navy destroyer in worldwide waters.
In an incident the Pentagon decried as "unsafe and unprofessional", a Chinese warship last month sailed within just 45 yards (41 meters) of a United States destroyer as it passed by Beijing-claimed features in the South China Sea, forcing the American vessel to take evasive action.
Wei and Mattis were in Singapore this week for an Association of Southeast Asian Nations.
The talks took place as the USA seeks to forge to more resilient military ties that can withstand mounting pressure between the world's two largest economies. Chinese military activity in the disputed areas is viewed by Washington as irresponsible while Beijing complains of an inappropriate US military presence.
Speaking to reporters traveling with him earlier this week, Mattis acknowledged that the relationship has been hard in recent times.
"We need to make sure that when we step on one another's toes it doesn't escalate into something that would be catastrophic", he said.
As recently as June, when Mattis was in Beijing for his first visit to China as Pentagon chief, President Xi Jinping called the U.S.
Schriver said both men spent "significant time" discussing the situation in the South China Sea, a flashpoint between the two countries.
Since then, however, a series of irritants have shaken military-to-military ties.
It is important to note that while President Donald Trump continues to be antagonistic towards China, the Pentagon, the country's military arm, continues to act as the voice of reason and moderation when it comes to dealing with the Asian superpower.
It appears to be aimed at striking a balance between China and the U.S. - the two major powers with considerable influence in the region, especially in the South China Sea/East Sea.
China expressed disappointment to Mattis on Thursday over that decision, Schriver said.