Motherwell were defeated by a classy Celtic outfit at Fir Park on Wednesday night, writes Craig Goldthorp.
New boy Rolando Aarons - on loan from Newcastle United - produced an early run down the right wing for the Steelmen and produced enough good play on the night to suggest he will be a useful acquisition.
After Odsonne Edouard had a shot blocked for Celtic, Aarons' shot from distance at the other end was comfortably saved by Fraser Forster.
The Steelmen then had a chance when Aarons found Chris Long whose miskick went to Jermaine Hylton who shot off target.
Celtic took the lead in eight minutes when a quick breakaway by James Forrest released Edouard whose initial shot was blocked by Peter Hartley before Edouard converted the rebound.
Motherwell almost hit back instantly when Long released Allan Campbell who shot wide. Celtic then raced to the other end where Leigh Griffiths missed a great chance by shooting over after Olivier Ntcham's cross from the right.
Motherwell continued to create chances, with midfielder Liam Polworth sending a long ranger well over the crossbar.
McGregor then sent an effort over at the other end.
A slick 31st minute swivel by Hylton made space for a 20-yard shot which was saved low by Forster.
Aarons then severely tested with a left foot shot which the keeper parried behind for a corner on 43 minutes.
Long failed to control the ball in midfield on 50 minutes and it was to cost 'Well dear as McGregor raced swiftly to the home penalty area and crossed for Griffiths to shoot home.
Polworth then sliced a shot wide on 53 minutes as 'Well tried to mount a fightback.
Motherwell substitute Sherwin Seedorf was played in by Hylton but shot weakly at Forster.
Skilful wing play by Edouard on 61 minutes saw him cross for Griffiths who headed against the bar. In the next attack Olivier Ntcham was played clean through but somehow blasted over from eight yards.
McGregor's left footer was saved by Gillespie before the keeper ran out and blocked from Edouard.
It was 3-0 on 75 minutes when McGregor finished magnificently after a fine Forrest run and cross on the right.
Edouard then advanced into space and flashed a left footed effort wide.
But it was 4-0 on 80 minutes when Edouard rammed home a free-kick from the edge of the box with Gillespie rooted to the spot.
Motherwell: Gillespie, Carroll, Grimshaw, Hartley, Campbell, Long (Manzinga 70), Hylton (MacIver 70), Aarons (Seedorf 56), Polworth, Donnelly, Gallagher.
Referee: Don Robertson