Chris Wilder reveals why he's excited by new signings ahead of possible Sheffield United debuts against Brighton

The pair, who signed for United on deadline day in January, joined the rest of Wilder's squad in Dubai last week.

Živković has gone through a fitness programme devised to bring him up to speed after his move from Chinese side Changchun Yatai, while Retsos is seen primarily as cover and competition for Chris Basham after signing from Bayer Leverkusen.

The pair joined fellow new boy Sander Berge in Dubai and Wilder said: "I've been delighted with the shape of all three.

"They passed rigorous tests and medicals, and all are really good athletes.

"Richairo hasn't played much football since the end of the Chinese season but has had a mini-pre season and Panos has been on the bench in the Champions League.

"Panos can play right centre-half and right wing-back and can also play in the middle of the park too. He's played for his country as well as two big clubs in Olympiakos and Bayer Leverkusen.

"Rich has obvious pace and a stretch in the team, which we wanted. And we've all seen what Sander is capable of.

"They're all good kids, really nice lads, who want to do well for themselves and fit in seamlessly. I'm not surprised, but the group as ever has been very welcoming and inclusive.

"It always fills me with a great sense of pride, how the group are as human beings and how they go about their business."