Golden State Warriors fans react as they watch a live broadcast of game four of the NBA Finals with the Cleveland Caveliers during a watch party at Oracle Arena on June 9, 2017 in Oakland, California.

Someone paid $133,000 to sit courtside at Monday night's NBA Finals game in Oakland between the Golden State Warriors and Cleveland Cavaliers, ESPN reports, citing a source.

They amount to the most expensive seats in NBA history, according to the report.

The buyer purchased the tickets from a season-ticket holder on the team's official resale site Sunday night, ESPN said. The face value price is unknown, though some courtside seats cost $3,000, ESPN reported, citing a document that the Warriors sent fans last year.

CNBC reached out to the Golden State Warriors and NBATickets.com, but neither could confirm the sale.

The Warriors are up 3-1 in the series and are looking to win their second title in three years at home.

Buyer fees on the site are 15 percent, so the buyer spent more than $17,000 on fees alone, according to ESPN. The average ticket price on the site for the game is $1,731, ESPN reported, nearly 20 percent higher than last year's Game 5 between the Warriors and the Cavaliers, when the average reached $1,444.

The purchase wasn't the only top-dollar one for the game. One pair sold for $90,000, and another sold for $82,000, according to ESPN.

CNBC's Michael Sheetz contributed to this report.

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