"It's a breakthrough in London, because people just do not associate us with local government in London, because we've not been here," he told City A.M. at City Hall.
He added: "Now we are here we're going to prove ourselves and if we do that next time round it'll be much easier."
Farage will have even more reason to celebrate after his party won seven seats in the Welsh Assembly.
Speaking about the EU referendum, the Ukip leader and MEP said: "I think the Remain side is probably slightly ahead, but I don't think it's very far ahead. So I think it's all to play for, literally all to play for."
Recent polling would agree, largely finding more support for Remain than Leave ahead of the vote on 23 June.
Yet Ukip faces a unique challenge in trying to reposition and make itself relevant for a post-referendum world, making today's gains more meaningful.