Chevron can now go ahead with its $53 billion deal to buy Hess, after winning a legal fight against ExxonMobil over valuable oil assets in Guyana.

The disagreement was about Hess’s 30% share in a giant oil field off the coast of Guyana called the Stabroek Block, which holds more than 11 billion barrels of oil. Exxon, which owns 45% of the project, and China’s CNOOC, which owns 25%, claimed they had the right to buy Hess’s share first. But Chevron and Hess argued that rule didn’t apply since the whole Hess company—not just its share—was being sold.

An international arbitration panel agreed with Chevron, clearing the way for the deal to continue. This is a big win for Chevron, which sees the Guyana oil project as key to its future growth.

Following the news, Hess shares jumped 7.4% and Chevron’s rose 3.6%. Exxon’s shares dipped slightly. While Exxon said it didn’t agree with the decision, it accepted the ruling and said it would continue working with Chevron in Guyana.

The legal battle lasted over a year and caused delays in the deal, but with the matter now settled, Chevron is expected to complete the acquisition and strengthen its position in one of the world’s most promising oil regions.