When OPEC and its allies met last month, Saudi Arabia’s energy minister dared oil speculators to test his determination to stabilize global markets.

Now that a resurgent pandemic is threatening demand once again, the moment of reckoning is getting closer.

The coalition of crude producers gathers Monday to assess the state of the market. No supply decisions are expected until Dec. 1 but leading members Saudi Arabia and Russia are already stepping up diplomacy. Russian President Vladimir Putin and Saudi Arabia Crown Prince Mohammed Bin Salman have spoken twice by phone in a week — the first time the countries’ leaders have done that since the depths of the oil crisis in April, when they were hashing out a deal to cut supply and bring the price war to an end.