While releasing a series of specs last week for Cybertruck, which is scheduled to start deliveries as soon as late 2021, Musk called up a video of the the pickup in a tug-of-war against Ford’s best-selling F-150.

He tweeted a clip of the test on Sunday showing his vehicle pulling a screeching Ford model up a hill.

Ford thinks Musk was making an apples-to-oranges comparison. The video the Tesla chief executive officer tweeted appears to show a two-wheel-drive version of the F-150 against an all-wheel-drive Cybertruck.

Other details that could have factored in which pickup won out include curb weight and tire type.

Sundeep Madra, vice-president of Ford X, the automaker’s unit for developing new business models, challenged Musk on Monday to send Ford a Cybertruck.

He linked to a post by the car-enthusiast site motor1.com that questioned whether Tesla’s test was “fair game.”

Tesla and Ford have been at this before. More than a year after Musk tweeted a boast about how much weight Tesla’s truck would be able to tow, Ford released a promotional video of an electric F-150 prototype dragging more than 1 million pounds of double-decker rail cars.

LISTEN: What do car dealers think about electric vehicles? Are they keen to have them in their showrooms? We talk to Vancouver GM dealer Blair Upton about this and much more during this week’s episode of Plugged In.