"I feel good," he told evertonTV. "It was great to play here for the first time. The fans were tremendous, as I have heard, and it was great to score my first goal. But it is tinged with bitterness because we didn't win the game.
"Hopefully it is a sign of things to come because at my other clubs I have got eight or nine goals a year. Hopefully as I get settled in I will get more goals."
Everton defender Phil Jagielka said: "It was a great finish from Casti.
"He's got some of the biggest legs I've seen so the power he got behind it wasn't surprising! I think his overall game was fantastic and hopefully he will be a great addition to the team."