Chevron Corp. has prevailed in a 20-month fight to buy Hess Corp. for $53 billion, overcoming a challenge by arch rival Exxon Mobil Corp. that was unprecedented in the modern history of Big Oil.

The conclusion of the saga removes a stock overhang for Chevron and paves the way for the $53 billion deal to close immediately, which the oil giant said it could happen within a couple of days.

Chevron Corp. won its arbitration battle with Exxon Mobil Corp. and has closed its $53-billion deal to buy Hess Corp. more than 20 months after the takeover was announced.