Cadillac driving down the road.

General Motors took a subtle jab at Tesla in a new commercial released this month, which saw a surge in interest over the weekend as fans of Elon Musk’s electric car flocked to survey the competition.

The ad shows a Cadillac CT6 driving on the highway without the driver touching the steering wheel, flanked by a Tesla Model S to the right. The driver invokes the “Super Cruise” driver assistance feature and crosses his arms, with the semi-autonomous system guiding the car along the highway without interaction. The ad subtly implies that the feature works better than Tesla Autopilot, which uses sensors to check that the driver has their hands on the wheel at all times in the driving mode. It’s a small dig at Tesla’s requirement, but fans have weighed in.

“What’s the matter Cadillac?” a YouTube user called “chookalana” wrote in the comments under the video. “Tesla got you scared? First rule of advertising, never mention the competition. It makes you look weak. “

Watch the ad below:

Tesla Autopilot is a key selling feature of the electric vehicles, in part due to the future potential. Musk claims that every Tesla shipped since October 2016 has the necessary sensors for full autonomous driving at a later date — tentatively scheduled for this year. Some fans noted Musk’s broad multi-year ambitions for projects tied to Tesla, including full autonomy and solar energy.

“REAL navigation - to me at least - would be if you could launch one of your cars into space, navigate it across the entire solar system, and land the booster rockets upright back on the launch pad, to the cheers of millions!” a YouTube user called “Eric Fontaine” said below the Cadillac video, referencing Musk’s SpaceX venture launching his red Roadster into Mars’ orbit last month using a Falcon Heavy.

Super Cruise may have only arrived last fall, but it has been described by The Drive as “everything GM promised” and “excellent.” With this latest ad, Cadillac has thrown down the gauntlet in the race to automate the car.