Amazon’s first “Thursday Night Football” Prime Video broadcast averaged 13 million viewers, according to data from Nielsen. For its part, Amazon reported that, including its own first-party data, the Sept. 15 game between the Los Angeles Chargers and Kansas City Chiefs brought in 15.3 million viewers across all platforms.

Amazon’s linear broadcasts in each team’s local markets, Los Angeles and Kansas City, drew audiences of 602,000 and 555,000, respectively.

Both Nielsen’s and Amazon’s final audience numbers surpassed Amazon’s initial estimates of 12.5 million viewers shared with advertisers in dealmaking pitches. According to Amazon, its performance last Thursday is also up 47% from last year’s second-week game on NFL Network, which averaged 8.8 million viewers.

One media buyer told Ad Age the first game’s viewership is “an outstanding result for Amazon,” with the caveat that the strength of the Chargers-Chiefs matchup likely influenced the strong performance. “I would expect more modest results in the coming weeks,” said the buyer.

These numbers come a full week after Amazon’s first “Thursday Night Football” stream. According to a Nielsen spokesperson, the delay was due to “additional quality control reviews of the ‘Thursday Night Football’ viewership data on Amazon to ensure accuracy before delivering it to our clients and partners.” 

The lengthy period between last week’s game and today’s Nielsen report raises new questions about how well and how quickly Nielsen will be able to report numbers on streaming audiences as it transitions to its next-generation Nielsen One cross-platform measurement.

The one-week turnaround appears at odds with Nielsen’s contention that it will still deliver overnight program ratings when Nielsen One launches, despite reports from people who’ve heard from Nielsen executives that it will move away from overnight ratings as the new platform rolls out. 

Spokespeople did not respond to a question of how it will be possible to deliver overnight ratings in the future when it takes a week to process data for a single streaming program at this point. 

Even after the delay, there was still a 2.3 million-person difference between Nielsen’s 13 million audience count and Amazon’s 15.3 million estimate. And it’s not clear how easily that can be resolved. While Amazon should know exactly how many households were tuned in, Nielsen needs to rely on its household panel for estimates of how many people in each home—or out of home—were watching.

Getting big data feeds from smart TVs and set-top boxes and using panel data to estimate person-level viewing is at the heart of making Nielsen One work. But it’s been an uphill push, with Video Advertising Bureau CEO Sean Cunningham saying that discrepancies between Nielsen’s big data numbers and its panel have continued without obvious improvement since March.

Nielsen advised clients not to use its Nielsen One test data as currency in deals in a memo last month. But a spokesman said that doesn’t indicate any unforeseen data issues or a delay in plans to launch the new measurement next quarter and have it fully ready as upfront currency by the 2024 upfront.

As for the upside for Amazon, the company released a statement from Jay Marine, Prime Video’s VP global head of sports, earlier this week, stating that the streamer’s first “Thursday Night Football” was “the biggest three hours for U.S. Prime sign-ups ever,” inclusive of the mega-retailer’s annual Prime Day deal event and shopping holidays Black Friday and Cyber Monday.