Not yet. But the thing is, from what I see Ukraine hasn't lost what it needs to hold in order to win. Mainly, the Dneiper Line, its Capital and Kharkiv. Ukraine executed a nearly flawless defense in depth strategy, which traded space for time while committing to defending the strategic points that absolutely had to be held. Irpin, Kharkiv and Mariople. Mariople is probably going to go, but the other two are going to hold. Which is huge, because it means that not only will the Ukrainian government remain a legitimate force, but Russia will fail to get to the part of Ukraine that actually matters for its warfighting capability. The portions west of the Dneiper. The fact that Russia has also failed to dislodge the Ukrainian regulars from the Donbass also means that mounting a counter attack in the south and east will be much easier.
Everything Russia gained it gained in the first 72 hours when they had strategic surprise. Since then its been a slow and grinding push back. Its not victory yet, but its definitely not defeat.