Livingston created the first scoring chance after four minutes when a long punt forward found Ryan Hardie, who held off Charles Dunne to lay the ball off to Lee Miller. But Miller's weak shot was straight at Mark Gillespie.
And the Lions had another chance when Craig Sibbald's corner from the left found the head of Alan Lithgow 12 yards out but his effort didn't really test Gillespie.
The Steelmen took the lead after nine minutes when David Turnbull's brilliant free-kick delivery from the left touchline was simply headed home by Liam Donnelly. The defender was only starting the match as Carl McHugh - whose name was on the official team sheet - was withdrawn at the last minute.
It was almost 2-0 on 16 minutes when James Scott took a Gboly Ariyibi pass and sent a low, powerful shot wide of the far post.
But Livi soon created an opening which saw Hardie's 20-yarder sting Gillespie's palms.
Motherwell went 2-0 up in sublime fashion on 21 minutes thanks to a fantastic corner routine. Ariyibi's short flag kick was flicked on by Scott to Turnbull who shot home emphatically.
And it got even better for the hosts within three minutes. Sibbald fouled the tricky Ariyibi in the box and Turnbull stood up to comfortably score from the spot.
Livingston should have pulled a goal back on the half hour when Hardie controlled a cross from the right but his effort from point blank range was blocked by Gillespie.
And Hardie should then have scored for the away side in the next attack but he shot well off target after fine build-up play also involving Hakeem Odoffin and Scott Pittman.
Scott was having a lively game for the Fir Parkers and he advanced impressively on 34 minutes before striking a left footer into the side netting from outside the box.
An incredible sequence late in the first half saw penalties missed at both ends.
Tom Aldred's foul conceded a penalty to the visitors but Hardie's effort from 12 yards was brilliantly stopped by Gillespie.
Play then raged to the other end straight away, with Turnbull brought down in the box by onrushing keeper Stewart. But Turnbull's resultant spot kick was saved by Stewart.
And Scott produced a fine piece of skill on the touchline early in the second half before passing to Cadden whose fizzing low shot was saved.
Livingston's Odoffin fired over the bar and it was almost 4-0 at the other end on 73 minutes when Turnbull charged down keeper Stewart's attempted clearance and fed Cadden, whose rasping drive was blocked.
But the visitors did net twice in quick succession to pull it back to 3-2 and it was substitute Scott Tiffoney who got both.
Firstly he finished at the back post after an initial header following a Steven Lawless corner had been saved.
And then Tiffoney was sent through on Gillespie and shot low past the custodian with eight minutes remaining.
Another long punt forward then found Tiffoney again but Donnelly blocked his shot from outside the box.
Motherwell: Gillespie, Tait (Cornelius 77), Aldred, Cadden, Campbell, Ariyibi (McHugh 87), Grimshaw, Dunne (Devine 61), Donnelly, Turnbull, Scott.
Referee: David Munro