Travis Kelce might have some competition when it comes to the top spot on Patrick Mahomes' BFF list ... 'cause Lionel Messi sure seemed to make a great case for it recently.
The soccer superstar hit a gym with the Kansas City Chiefs quarterback to film an adidas ad ... and the guys appeared to have some serious bromantic chemistry both on and off camera.
In the 45-second, Three Stripes advert ... Messi can be seen pushing Mahomes to run faster on a treadmill -- which Patrick appreciates.