During his time at Chelsea, the club consistently finished in mid-table, and narrowly missed out on relegation to the Second Division in 1951 on goal average. However, Birrell guided Chelsea to two FA Cup semi-finals, in 1950 and 1952, on both occasions losing out to Arsenal in replays. He retired following the latter defeat. He also played a significant part in the development of the club's youth system, which was to pay dividends for future managers.