Can someone explain the logic to me

[Legends of Sport]

I love the Grand Slams but dont really follow the minor tournaments so I dont know the reason. But (Im pretty sure) it was on the first championship point, Federer served a fault, then second serve got called a fault, Federer challenged and was correct, and then by MAGIC, he got a first serve again. How is this possible? Surely he should get the second serve again. This just lacks common sense to me. Can someone explain this to me please.

Thanks,
Dan (LOS)
Roger and Rafa history: https://www.youtube.com/channel/UC4tN5hCHizV-kwzPmcLjzXg

 

[Legends of Sport]

Thanks!