No fighter in the history of the UFC had been champion in two weight divisions simultaneously but that all changed as Conor McGregor dethroned lightweight title holder Eddie Alvarez at UFC 205.

Featherweight champion McGregor made history in New York City on Saturday after beating Alvarez by knockout in the second round.

McGregor was superior from the opening bell at a sold-out Madison Square Garden, producing a masterclass with timing and precision to leave Alvarez rattled.

The Irish star knocked down Alvarez early in the opening round and he floored him again twice before the second but the American somehow survived.

Alvarez, though, did not last much longer as McGregor continued to connect with his left hand, delivering the killer blow with a four-punch combo.