 McDermott won his first match as a head coach against Castleford Tigers.He went on to claim 5 wins and 4 losses in the remainder of 2006.McDermott remained at Harlequins for a further four seasons but the team decreased in performance, dropping from 7th to 9th then 9th again then 11th and finally to 13th and did notmake the play-offs in any of those years, with most seasons seeing a second half collapse; the 7th-place finish in 2006 being his highest with Harlequins.