Martin O'Neill says he's been pleased with Simon Mignolet's progress during his reign so far.
The big Belgian was rested for the draw with Bolton recently but returned for the 2-1 defeat at Fulham last weekend.
Mignolet made a number of important saves, including a superb late block to deny Moussa Dembele.
The stopper, signed from Belgian club Sint-Truiden in summer 2010, has proved a shrewd acquisition and has established himself as number one at both club and international level this season.
He has made 34 appearances this season and O'Neill believes he is becoming a top performer.
Speaking after the defeat at Craven Cottage, the Sunderland manager said: "Simon made some key saves for us.
"He's developing into a very, very decent goalkeeper and I'm very pleased for him."