Sunderland and Southampton have played out a goalless first-half at the Stadium of Light in the fifth round of the FA Cup.
The Saints fashioned the first clear-cut attempt at goal, with Rickie Lambert nodding an Adam Lallana cross into the path of James Ward-Prowse, only for the youngster to see his effort saved by Oscar Ustari.
Mauricio Pochettino's troops may have found the breakthrough on 36 minutes if not for the intervention of Santiago Vergini, who produced a crucial interception to deny Lambert from reaching Nathaniel Clyne's cross.
The Black Cats spurned a good opportunity to edge ahead with five minutes remaining in the half, with Fabio Borini and Emanuele Giaccherini leading a swift counter-attack, but the Liverpool loanee failed to pick out his advancing compatriot.
