'Embarrassing for Putin': Russian territory is under occupation for the first time since WWII

Sinai in the Yom-Kippur

I think that seems reasonable fair to count?

Edit: US Gov was convinced in '75 but that's only by the point they were convinced, and its quite possible it was prior.

Edit: just reading more, but this was a pretty cool event from the war

The Egyptian Army put great effort into finding a quick and effective way of breaching the Israeli defenses. The Israelis had built large 18-metre (59 foot) high sand walls with a 60-degree slope and reinforced with concrete at the water line. Egyptian engineers initially experimented with explosive charges and bulldozers to clear the obstacles, before a junior officer proposed using high pressure water cannons. The idea was tested and found to be a sound one, and several high pressure water cannons were imported from Britain and East Germany. The water cannons effectively breached the sand walls using water from the canal.