Hilarious for them to act like the Su-57 (Russia’s fifth gen option) is truly comparable to ether F-35 or China’s J-20. To my understanding, the Su-57 is highly optimized for dexterity and maneuverability in dogfighting, but that doesn’t mean shit when you’re dealing with the stealth, sensor, and range capabilities of an F-35 or J-20. It’s for this reason that some have referred to the Su-57 as a ‘4.5th gen’ fighter, as it lacks several of the stealth and sensor integration capabilities of its fifth gen peers.

Anyways, I doubt that the US is really worried about Russia’s offering here, but I’d bet they are very worried about China’s.