The 25-year-old has played the vast majority of his recent rugby at inside centre and that is where his eight England caps have come.
He was parachuted in to join the Lions this summer amid a host of injuries to Warren Gatland's backline and made tour appearances in Australia, and Davies was full of praise for his recent form.
"Billy adds another dynamic," he said. "Freddie [Burns] has not been on the top of his game and he openly admits that so to take him out of the firing line was very important.
"This game has been on the horizon for a while. The key thing from my players' point of view was we were under a lot of pressure and they showed good character in a typically hard-fought derby match."