The Hull-born forward, 18, briefly gave the Tigers’ hope with an 81st-minute strike ahead of the hosts sealing the game with a third goal in stoppage-time.
McCann, who will be without Josh Magennis (hamstring) for the next six to eight weeks, with Kevin Stewart (out) until February, said: “He is a good player and can play anywhere across the front line, which is good as I like that ability with people playing in different positions. Keano gives us that bit.
“I am sure he will keep his feet on the ground. He is a great boy and just wants to get better.”
Collectively, it was an ‘After the Lord Mayor’s Show’ moment for Hull after their 4-0 midweek thumping of Preston and midfielder Josh Bowler offered no excuses.
He added: “I think we just did not turn up from the first whistle to the last.
“It was not the standards we set ourselves and we all know that and are disappointed.
“We need to go back on Monday and work on it.”
By contrast, Barnsley head coach Gerhard Struber was a proud man after witnessing his Barnsley side display character and quality in a special first home game in charge as the club ended their second worst run of form since 1952-3.
Struber, whose name was sung by supporters in the second half and at the final whistle, said: “All together, it was very good and I was very proud for my boys and this atmosphere was amazing.
“I am happy. It was a special situation for me.
“I have been here for 10 days and this is our first small step in the right direction and we want more.”