Leeds United won 2-0 at Oakwell on Saturday as the cream rose to the top.
First-half goals from Samu Saiz and Egzjan Alioski gave Leeds all three points in yesterday's Yorkshire derby.
It was in-form Saiz, who has five Championship goals this season, who ran unmarked toward Barnsley's goal and drilled home the opener on 23 minutes after an eye-of-the-needle pass from Alioski, who stroked home a second from the edge of the box just before half time.
Asked on BBC Radio why the Spaniard was allowed to run so far unchallenged for the first goal, Heckingbottom said defensive midfielder Joe Williams should've been in the area, but believes the pass from Alioski was simply "first class".
The Tykes boss said: "He [Saiz] is a good player isn't he. Nine times out of 10 if you ask Joe where he's going to be then he'd be there [marking Leeds man] but then Saiz is just going stand somewhere else.
"The ball into him for the goal was first class and that was the difference. Leeds showed that they got some quality players today."
He is right. Leeds, when they're on form, are a fine football team and two wins from three games this week should fill them with a lot of confidence ahead of next week's visit of in-form Aston Villa.