The live internet stream of double Formula 1 world champion Fernando Alonso's first IndyCar test attracted more than two million views on Wednesday.
Although the Spaniard's first experience at Indianapolis was a private test arranged by McLaren, Honda and Andretti Autosport, the circuit put on a proper broadcast of the event involving a studio panel, in-depth interviews and fly-on-the-wall access.
The test, Alonso's first experience of the Dallara-Honda prior to his surprise Indianapolis 500 debut, was broadcast live on YouTube and Facebook.
Reaching peaks of more than 70,000 concurrent viewers at times, the official figures recorded by YouTube and Facebook showed a combined overall viewership of 2,149,000 views.
This was split up between 950,000 views on IndyCar's official Facebook page and 1.2 million viewers on the official IndyCar YouTube channel on YouTube.
It was also one of YouTube's top ten trending videos of the day.
These numbers exceed what many popular categories, like F1 and MotoGP, get for race highlights and incidents, as Alonso's IndyCar effort continues to capture fan attention.
The popularity of this video of a midweek, single-car test has already prompted suggestions that F1 could learn lessons from what has happened.
Indianapolis's Alonso coverage included access to his conversations with engineers, his run programme and feedback as he built up his speed.
Sky broadcast a pre-season Barcelona test live back in 2013 but the effort was not repeated because the expense of doing so outweighed the level of interest from fans.
However, in F1 testing, cars are kept hidden behind screens and camera crews are given very limited access to drivers and engineers, so are unable to generate the kind of interest that IndyCar was able to do with Alonso on Wednesday.