Jack Ross hailed Jon McLaughlin's professionalism after the latest heroics from his summer signing.
McLaughlin did not travel south with the team on Friday as he awaited the birth of his second child.
He arrived late on Friday night and went on to produce an inspirational display between the goalposts.
A pair of outstanding saves in the second half, from Graham Carey and Freddie Ladapo, kept the Black Cats 1-0 up before Aiden McGeady's penalty settled the contest.
"He had a second child, a son on Thursday. He came down very late last night, it is testament to his professionalism," Ross said.
"He only arrived at the hotel after 11pm on Friday but produced another fantastic performance, producing a couple of fantastic saves in the second half.
"It was a planned birth, a caesarean, which is a little more organised, selfishly it helped me as we could plan around it.
"He had Thursday off and then didn't travel until late last night."
The 31-year-old kept his fourth consecutive clean sheet in the league at Home Park, a vital component in Sunderland's rise to the automatic places.