A group of unsecured creditors pushed to derail the sale of bankrupt gym chain Blink to a UK company after it won an auction over Planet Fitness, The Post has learned.

Planet Fitness -- the largest gym chain in the US with more than 2,000 locations -- had made an 11th-hour bid to acquire Blink, which last week accepted a lower offer from UK-based Pure Gym, sources exclusively told The Post.

Pure Gym -- which opened its first three gyms in the US in 2022 -- last week submitted a $121 million winning bid to win the auction for Blink as the UK company seeks to expand. The company aims to open as many as 300 gyms in the US over the next five years, according to an April press release.

But on Friday, in the closing hour of the deal's 48-hour challenge period, Planet Fitness submitted two larger competing bids: $141 million if no premerger regulatory filings were required, and $153 million if Planet Fitness had to submit the paperwork.

Blink's debtors made a filing Monday night in support of Pure Gym's initial offer, saying the sale process "culminated in the highest and best bid with a well-financed strategic buyer," a source close to the process said.

The proposals will be considered in Delaware bankruptcy court on Wednesday.

Planet Fitness did not immediately respond to a request for comment.

Planet Fitness first made a bid on Oct. 23 to acquire Blink and its approximately 60 locations after the company filed for Chapter 11 bankruptcy protections in August, a source close to the matter told The Post.

The offer was discarded by the debtor and the investment bank overseeing the auction over concerns that the acquisition would face lengthy antitrust challenges that could prevent Blink from emerging from bankruptcy since the company is running on just 30 days of cash, the source said.

Blink was founded in New York City in 2011. The low-price gym chain charges between $15 and $40 a month for memberships, according to its website. Blink is owned by Equinox, a luxury fitness club whose upscale gyms charge upwards of $500 a month for its memberships.

Blink's prices rose to between $22 and $45 a month at NYC locations following some price hikes over the past few years. The company also owns locations in New Jersey, Pennsylvania, California, Illinois, Massachusetts and Texas.

But like many others, Blink fell victim to the pandemic-era gym drought that popularized free at-home fitness videos. Gyms have yet to see these consumers, who have been hit hard by sticky inflation, return in full swing.

Soon after the company filed for bankruptcy, it announced it would be closing about 10% of its gyms. Blink has continued operations at its remaining gyms throughout the sale process.