The yen’s two-month rally from its October low is coming under threat after the currency slipped below a key support level, opening the door for it to start weakening again.

The currency fell for a fourth day Friday following stronger-than-forecast U.S. employment data, dropping further below a support line starting from October’s three-decade low. It fell as much as 0.9% to ¥134.59 per dollar, its weakest since Dec. 20.

November’s 3.8% decline in real earnings from a year earlier, the most since May 2014, also weighed on the yen. It extended losses after a report that Bank of Japan officials see little need to rush to make another adjustment to its yield-curve control policy.

Yen bears are now awaiting Friday’s U.S. payrolls numbers, which may confirm a tight labor market is adding to inflationary pressures, backing the Federal Reserve’s pledge that it still has a "ways to go” in raising interest rates.

Stronger-than-expected U.S. employment data may see dollar-yen risk testing its 200-day moving average of 136.48, said Patrick Bennett, a strategist at Canadian Imperial Bank of Commerce in Hong Kong.