The James McFadden-inspired hosts overcame an early Hibs goal to guarantee their place in the top six ahead of the split. Tom Taiwo's strike gave Hibs a half-time lead but a fabulous second half from the home side, which produced goals for Michael Higdon, McFadden, Kallum Higginbotham and Tom Hateley, sealed an emphatic win.
"I was disappointed to go in at half-time a goal behind as I thought we played well in the first half," said McCall, who also lost midfielders Keith Lasley and Nicky Law to injury in the first half.
"At half-time I was more concerned about the changes we needed to make having lost both Keith Lasley and then Nicky Law, but I thought we completely controlled the second half and scored four great goals. It was a really good night's work by the players, but having made sure of a top-six finish we must keep it going."
McCall was glowing in his praise of McFadden but cautious about him being ready for a Scotland recall.
McFadden turned in a man-of-the-match display as he completed his first full game since September 2010, but McCall said: "McFadden is an eye-pleaser and gets the fans off their seats. His crosses and the way he ghosts past players is terrific and he topped his performance with a great goal.
"But it is too early to talk about him getting back into the Scotland squad."
Hibs boss Pat Fenlon made no excuses after the match, saying: "I am very disappointed but we deserved nothing from the game. We were probably lucky to be in the lead at half-time. In the second half we were very poor and James McFadden very good.
"But we knew Motherwell would come us at the start of the second half. To concede three goals in 15 minutes should not happen with the experienced players we have. We still have to apply ourselves in the next two games if we want to make the top six.
"We didn't do enough - we were not good enough."