After a 20-month spell in South Africa playing for Port Elizabeth City, he returned to London in November 1967 to join Leyton Orient.
Born and brought up in England, after a chance conversation with QPR teammate Don Givens, Mancini found out that through his Irish father, he could play for the Republic of Ireland.
Mancini was deemed surplus to requirements (being nearly 34) by Mee's replacement Terry Neill, and he was released on a free transfer in September 1976.
He ended his career in the NASL, playing one summer with the Los Angeles Aztecs before returning to England As well as playing, during the early 1970s Mancini was an occasional presenter of London Weekend Television's The Big Match, when the programme, in an attempt to distance itself from the more staid Match of the Day, experimented with using current players as presenters.
Williams' diary entry for that day includes: " When he (Mancini) left, he said to me ' I could stay here all night taking to you...I'd like to meet you again...this could go on forever as far as I'm concerned'.