Ukraine's Stunning Fightback: Is Russia Losing The War?

Ukraine's army, which was sustaining heavy losses, appears to have turned the tide on the Russians capturing 6000 sq kms of territory in the East and in the South of the country . The pace at which this has happened is truly incredible. In fact, it's going to be studied for years. How has this happened? Are Russian forces truly on the run in the East? Can Ukraine keep up with its offensive? Pushed to a corner, how will Russia react?