The euro sank Monday to $0.9878, its lowest since December 2002, despite expectations the European Central Bank will hike interest rates again Thursday to combat soaring inflation.
The shared eurozone unit has collapsed by about 13 percent against the dollar since the start of the year, hit also by the US Federal Reserve's more aggressive monetary tightening.
European stocks tumbled Monday while natural gas prices spiked almost a third, while oil added to strong gains as OPEC and its Russia-led allies decided at a meeting Monday to lower crude output in a bid to lift prices.
The news intensified an energy crisis caused by Europe's sanctions on Moscow for its invasion of Ukraine in February.
Investors are fearful of an energy supply crunch during the peak-demand northern hemisphere winter.
That could potentially lead to a painful recession.
"Russia's decision to turn off Europe's gas hangs over the continent like a grim shadow ahead of winter," said AJ Bell investment director Russ Mould.
At the same time, governments worldwide are grappling with the impact of rocketing domestic energy costs.
Germany on Sunday unveiled a new 65-billion-euro ($65-billion) package to help households cope with soaring prices, and eyed windfall profits from energy companies to help fund the move.
That took Berlin's total relief to almost 100 billion euros since the start of the Ukraine war.