Transplanting of Weeping Cherry Tree?

I dug out a small weeping cherry tree from an overgrown terrace. It is about 5 feet tall, with a trunk about an inch+ in diameter. In the process of trying to wrestle out its roots, I managed to lose all the soil around the four prominent roots which I had to tear away from the ground. There were no small roots at all, nothing to really hold a "root ball" together.

Within an hour I had it replanted in a large, deep hole. The hole is dug into pretty hard clay, but the planting soil I used to bed it was good. It's been very hot, however, and it's planted in direct afternoon sunlight. The leaves shrivel during the day and look slightly better at night and into morning before the sun hits it.

We're only on day three of this experiment. If it's leaves don't perk up with very consistent watering, should we assume it has died on the operating table. Seeing those totally bare roots made me think it was a lost cause. Advice?

Thanks.

By Martha