Heidi Klum Wishes Germany Good Luck W/ Sexy Snap Before Euro 2020

Heidi Klum showed support -- or a lack thereof -- for Germany ahead of their UEFA Euro 2020 opener on Tuesday ... by showing off some serious underboob as she wished the squad good luck!!

The 48-year-old supermodel gave an incredibly sexy shoutout to her home country's football club ahead of their match against France ... saying quite simply, "Good luck today Germany."

Klum threw on a pair of black bikini bottoms, a gold waist chain and a cropped Germany jersey for the special message ... and giving a big smile and two thumbs up to the camera.

Now, Klum's never shied away from showing off some serious skin throughout her career -- after all, she's been on the cover of the Sports Illustrated Swimsuit Issue and a Victoria's Secret Angel.

Germany may need some more good luck vibes before their next match against Portugal on Saturday -- they just lost its close opener against France, 1-0 ... the first time the German national team has EVER lost an opening game of the Euros.