Chris Coleman has hailed the impact of Jake Clarke-Salter, but insists he wants to see even more improvement from the 20-year-old.
The Chelsea loanee has started both games since his arrival earlier this and Coleman says it has been a big boost as Marc Wilson battles back from an injury.
Coleman said: “He’s been good. He made one or two little errors, but that’s only his second game in two months.
“He’s short of match practice, but he’s not short of personality, determination. He means his defending. He’s been a real boost for us to have him because we lost Marc Wilson.
“We have three centre-halves there – Willo, Tyias (Browning) and John (O’Shea). Billy (Jones) can play there at a push, but we needed to bring one in.”
“There is a good balance and they’ve found a bit of togetherness and unity as well off the training pitch,” he added.
“We needed it against Hull City (last week).
“One or two moments, we could have done better defensively, and it was straight off the training pitch, which disappointed me a little bit.
“But I am being a bit harsh on them because they dug in and got a clean sheet and that’s five clean sheets in 11 games? That’s not bad.”
Clarke-Slater himself has praised the influence of veteran O’Shea alongside him and says he can learn from the Championship environment.
He said: “John’s seen it all and he was leading by example. He set the tone for us younger players around him.
“It’s a similar situation to what I used to have with John Terry – he’s been there, done that, won 100-odd international caps, so to learn from him is brilliant for me.
“It helps me and Tyias to have someone who’s been there and played in massive games for massive clubs, here at Sunderland and (Manchester) United. He sets the tone, gives me advice and helps me a lot through the game.
“I feel that, as a centre-back, I will learn a lot here – I’ll learn how to defend and I can learn from playing with experienced players like (Lee) Cattermole and O’Shea. I can only improve,” he added.
“The difference is massive from U23s football – the physicality, the pace of the game – but I’m hear to work very hard and hopefully improve as a player.
“I’m 20 now, so I wanted to get out, experience it all and hopefully improve. I feel like this is a perfect club for me to do it.
“It’s about moving on to the next step now for so many young players and hopefully I can do that now at Sunderland.”