'Celtic know what their roles are under O'Neill'

Watch Sportscene pundit Charlie Mulgrew discuss former club Celtic's transformation with the return of manager Martin O'Neill.

The defending Premiership champions won 4-0 in the Northern Irishman's first game back, following Wilfried Nancy's chaotic eight-match reign.

"There's definitely an energy shift in terms of the players are delighted," Mulgrew said.

"They know exactly what their roles are under Martin O'Neill. He manages the team, he manages people very well."