Gov. Andrew Cuomo’s campaign tore through $8.5 million over the last three weeks to repel Democratic challenger Cynthia Nixon, according to records released Wednesday.

New filings at the Board of Elections show Cuomo has spent about $16 million since July — nearly triple what he shelled out during an identical period in 2014 against Zephyr Teachout, who is now a candidate for state attorney general.

The governor still has $16 million left in his campaign kitty.

As part of its massive spending, the Cuomo campaign transferred $2.5 million to the state Democratic Committee, which has been running ads promoting him, running mate Lt. Gov. Kathy Hochul and attorney general candidate Letitia James.

Cuomo has flooded the airwaves for the Sept. 13 primary, including ads blasting President Trump and testimonials from former Vice President Joe Biden.

The governor’s campaign committee, Andrew Cuomo 2018, collected $166,756 in contributions over the last 21 days — including $10,000 from business mogul John Catsimatides and $5,000 from philanthropist Agnes Gund, among others.

The Nixon campaign reported raising $375,000 during the same period, mostly from small donors — plus another $100,000 in “in-house” manpower support from groups including the Working Families Party.

Cynthia for New York spent $450,275 and has $466,749 left for the home stretch.

Without the incumbent’s financial firepower, Nixon has relied almost exclusively on free social media and grassroots campaigning to get out her message.