Thorp Arch Academy product Mowatt, 18, has made his first-team breakthrough this season and was one of McDermott's better performers in his maiden Elland Road appearance as Leeds laboured to their first win in five matches against the 10-man Cherries.
"The crowd took to him straight away," McDermott said. "You can see what he's got. He can run, he can tackle, he can pass, he'll score goals, he's got a very level head and he's another one of our Academy players coming through.
"The bridge between the first team and the Academy now is a really good place and Neil has done a fantastic job for this club.
"Alex is not particularly loud, he's a quiet boy, but he's tough. He knows what he wants, he can score, his free-kicks are excellent as well and he's got a really good understanding with Ross McCormack.
"You can see the respect the players have got for him, they keep wanting to give him the ball and the fans want to see him on the ball and that's a really good sign.
"The other Academy players can see him in the first team and it gives them hope. If they're good enough they're old enough.
"Leeds have been great at producing their own boys over many, many years and it's great for them because they all want to play for Leeds."