Defender Bailly has praised the 26-year-old, labelling him the 'best goalkeeper in the world'.
“It's a good thing for us to have, in my opinion, the best defender, the best goalkeeper in the world," he told the club's official website.
“That gives us so much more confidence going into a match.
“David is very, very, very important for everything we do.
“The goalkeeper instills confidence not just in the defenders but in the whole team, so that's why I think David is very important to the whole team."
Bailly is confident he can continue his own rise to prominence under a manager Jose Mourinho who has installed confidence throughout the whole side.
“For me, the aspect that was very important and where I see improvements – and can improve even more, to be honest – is the tactics, as well as the high level of concentration that's required," the Ivory Coast international added.