Russia has been outgunned and outmanned since the annexation of the Kherson and Zaporizhzhia regions.
After an explosion ripped through the crucial bridge connecting the annexed peninsula of Crimea to the Russian mainland early on Saturday, they now face a far greater struggle to supply their frontlines.
Two of the bridge's road spans crashed into the sea and set a nearby railway shipment of fuel tanks ablaze, stopping all traffic on the route which the Russian military relies on to ship supplies and equipment into the war zone in southernUkraine.
Russia's president was humiliated when he drove a Kamaz truck over it to open the infrastructure link.
The smouldering bridge became a symbol of Russia's struggle to cope with the Ukrainian advance in the south-eastern part of the country.
Michael Kofman, a military analyst and director in the Russia Studies Program at a US defence think-tank, said the loss of the rail link would make it harder for Russia to move troops and supplies through the peninsula.
South-eastern Ukraine is the only other route for supplies. The land bridge that Russia has created is hard to cross. There are few and far between rail lines and they have to cross bridges over rivers and irrigation canals.
Russian forces were limited by Ukrainian missile strikes on the south.
According toPhillips O'Brien, professor of strategic studies at the University of St Andrews, Russia has lost a lot of trucks during the invasion.
It will be very difficult for them to make it up. The railway line needs to be moved heaven and earth in order to reopen.
O'Brien said that the disruption could helpUkraine to expand its counteroffensive.
He said that the Russians are in trouble. The Russian army is in a poor state. It is not a good thing. The supply is not good. The Ukrainian army is well trained and ready to fight. It is difficult to see the balance going towards them.
Even in Kyiv, the hopes of retaking the peninsula were seen as a pipe dream for years, but now seem less fanciful.
The attack on the bridge is the latest in a series of strikes on military infrastructure behind enemy lines.
The first six months of Moscow's "special military operation" evoked far off conflicts in places like Syria rather than the reality of war on Russians' doorsteps.
After Ukraine routed Russia's forces in the eastern Kharkiv region in September, Putin shattered that domestic illusion by moving to annex the four regions and threatening to use nuclear weapons to defend them.
The escalating has backfired. Tens of thousands of Russians have left the country to avoid the draft, as well as many who joined the army, because of Putin's claim that Russia is part of Ukraine.
The circumstances of the attack on the bridge are not clear. According to Russia, a truck was packed with explosives despite passing an inspection on the mainland.
Ukrainian officials gleefully celebrated the blast but have not confirmed their involvement while casting suspicion on Moscow's version of events and suggesting it could be part of security forces' infighting in the blame game for Russia's failures.
Russia's army has faced withering public criticism in state media and from some officials in recent days as they search for a scapegoat for the battlefield failures.
The war's most ardent supporters want Putin to destroy Ukraine's critical infrastructure.
We are villains for the west. One of Russia's most prominent state television commentators wrote on Telegram that he wanted to scare them instead of being a laughing stock. It's time forUkraine to be plunged into the dark ages. Bridges, dams, railways, power stations, and other infrastructure objects must be destroyed.
The net result is more important than the cause of the explosion.
Over the next several days or even weeks, Russia will most likely be forced to rely on the limited stock of weapons and other military supplies it already has on the peninsula to supply the front in mainland Ukranian. It may be necessary to be cautious about the rate of expenditure as the counteroffensive by the Ukranian army presses south.
The Kremlin said on Saturday that Putin ordered an investigation into the incident but had no plans to speak to the Russians.
One of the red lines that could bring about the worst case scenario was striking the bridge.
She said that experience showed that Putin always got around to reacting to military setbacks very late.
Within hours, authorities said they were reopening the bridge to road and rail traffic and that supplies of food and petrol would continue.
O'Brien said that Russia's ability to retaliate is limited by its own poor battlefield performance and lack of air superiority.
They have to do it from standaway missiles because they are afraid of flying overUkraine. The Ukrainians are good at intercepting enough of them that they can't do it.