Amazon is already seeing some fruits from its massive investment in live NFL streaming.

The company reported the “biggest three hours for U.S. Prime signups ever” during last week’s Thursday Night Football game, according to an internal memo sent by Amazon exec Jay Marine, obtained by GeekWire.

The Chargers vs. Chiefs game was the first of Amazon’s reported $11 billion, 11-year exclusive streaming rights deal with the NFL.

Amazon aired Thursday Night Football games for the past several years but this was the first exclusive stream, meaning the only place to watch the game was via Amazon. That requires fans, for the most part, to have a $139/year (or $14.99/month) Prime subscription.

Boosting signups for Prime is key for Amazon as the membership program is a crucial part of its business. Surveys have shown that Prime members spend considerably more than non-Prime members on Amazon.com.

Adding more subscribers is also timely as competitors such as Walmart and Target roll out or bolster their own membership programs. Even companies like Disney, which has invested heavily in streaming, are reportedly looking to offer similar programs.

Amazon certainly used the game as an advertising vehicle for Prime, promoting the program and content such as Amazon’s new Lord of the Rings show with advertisements.

The company increased the annual cost of a U.S. Prime membership by $20 to $139 earlier this year to help offset increased costs due to labor supply shortages, higher wages, supply chain issues, and additional shipping expense. That sparked The Washington Post to roll out an interactive quiz, helping customers figure out if the membership is worth it or not.

In addition to streaming live sports and other video content, Prime benefits include free shipping, cloud storage, discounts at Whole Foods, and more.

Amazon reported $8.7 billion in subscription service revenue in the second quarter, up 10% year-over-year. There are more than 200 million Amazon Prime members worldwide.

Marine’s memo also noted that the Thursday Night Football broadcast was the “most watched night of primetime in the U.S. in the history of Prime Video,” and that viewership exceeded expectations. He also called the stream a “huge technical achievement” given that it streamed without major outages or delays.

Amazon’s NFL deal is the latest example of live sports moving online and away from traditional cable TV, with tech giants including Apple bidding for lucrative streaming rights.