League leaders Doncaster took the lead near the end of the first half with a superb low strike from Tommy Rowe.
The O’s equalised just before the break through an unlikely source, as Tom Parkes slotted home to level the match up.
Former O’s striker John Marquis regained the advantage for the visitors with another clinical low strike, after an Orient mistake.
He grabbed his second late on to slot in from close range. Another former Orient player also got on the scoresheet Mathieu Baudry completed the rout shortly after with a great volley to secure all three points.
Danny Webb made five changes to his side they were defeated 5-0 away to Accrington Stanley on Tuesday, as Alex Cisak returns to the side between the sticks ahead of Charlie Grainger. Along with Liam Kelly, Aron Pollock, Nigel Atangana and Michael Clark who replaced the injured Nicky Hunt (Knee) and Callum Kennedy (Groin), with Freddy Moncur and Sam Dalby dropping to the bench repectivly.
Orient were the first to have a threat on goal, as Sandro Semedo’s corner was not totally cleared by Doncaster and Clark header from the clearance went just over the bar from inside the box.
Doncaster nearly took the lead 22 minutes in, when a looping cross into the box found John Marquis to head goalwards which was palmed away by Cisak at full stretch.
The visitors started to assert their pressure on Orient, as full-back Matty Blair whipped in the ball for Rowe to meet but was straight at Cisak.
Doncaster broke the deadlock nine minutes before the break, as Orient did not clear their lines properly and Rowe picked the ball up on the edge of the box and struck his shot low into the bottom corner beyond Cisak.
Orient equalised on the stroke of half-time, as Parkes carried on his run from his own box laid it off to Gavin Massey who fended off his man went passed another Doncaster defender and slotted in the unmarked Parkes who coolly tucked it passed Ian Lawlor – to go in at the break level.
In the second half, Doncaster almost regained the lead as the ball found its way into the six-yard box to Marquis who looked certain to hit the target but for a superb block by Parkes.
The away side did retake the lead, after a bad pass from Pollock straight into the path of Marquis whose shot went in off the post – out of the reach of Cisak.
Doncaster missed a great chance for their third, as Judd’s half clearance fell to Alfie May inside the box but he dragged his shot well wide of the target.
The away side spared another glorious chance, as they broke from an Orient corner and substitute Andy Williams was played in on goal but hit his shot well over.
Williams again was played through Orient’s own wrong doing and burst to the edge of the box but blazed his shot well over.
Doncaster grabbed their third with eight minutes to play, as Williams again broke free of the defence this time he squared the ball across goal for Marquis to fire past Cisak.
The away side got their fourth with four minutes remaining, as the cross came in and Baudry’s first time fierce volley flew into the bottom corner – to see off the O’s and take all three points.
Leyton Orient Lineup: 1 Alex Cisak, 4 Liam Kelly (C), 6 Tom Parkes, 7 Michael Collins, 11 Gavin Massey, 15 Nigel Atangana (88), 22 Sandro Semedo, 25 Aaron Pollock, 28 Josh Koroma (77), 29 Myles Judd, 34 Michael Clark,
Substitutes: 24 Sam Sargeant, 19 Teddy Mezague, 20 Rowan Liburd, 23 Freddy Moncur, 30 Sam Dalby (77), 31 Steven Alzate (88), 38 Dan Happe
Doncaster Lineup: 38 Ian Lawlor (45), 2 Craig Alcock, 5 Mathiey Baudry, 6 Andy Butler, 9 John Marquis, 10 Tommy Rowe, 17 Matty Blair, 24 Niall Mason, 25 Conor Grant, 26 James Coppinger (78), 39 Alfie May (72)
Substitutes: 13 Marko Marosi (45), 7 Gary McSheffrey (78), 11 Andy Williams (72), 12 Mitchell Lund, 14 Harry Middleton, 19 Liam Mandwville, 27 Cedric Evina
Attendance: 4,791 (816)
Morison Double Roars Lions to Victory
Millwall claimed back-to-back league victories with a first half brace from Steve Morison to seal a comfortable 2-0 home victory against Doncaster Rovers.
Morison bagged two within eight minutes from a defensive error from the Doncaster defence and a sweet strike, for sixth goal of the season.
Darren Ferguson woes continue as they fall to their second defeat on the trot and remain in the relegation zone, as Millwall climb to eighth.
Neil Harris made two changes to his side that won away at Sheffield United at the weekend. Carlos Edwards returned from suspension to replace Shaun Cummings, as Shane Ferguson is preferred to Fred Onyedinma who both move to the bench.
Millwall were gifted an early goal just five minutes in, as the Doncaster goalkeeper Thorsten Stuckmann gave a loose ball straight for Morison to intercept and poke his shot into an empty net.
‘The Lions’ doubled their lead within three minutes of the first, as a free-kick by Shane Ferguson was whipped in to an unmarked Morison at the far post to fire his first time volley into the bottom corner – his second in quick succession.
Rovers could have got themselves back in the game after lackadaisical defending gave Coppinger a chance to cut a fierce ball across goal, which Nathan Tyson could not turn on target.
Aiden O’Brien went bursting down the left flank as the Doncaster defender slipped, he then clipped a ball towards the far post for Lee Gregory whose stabbed shot was saved, by the legs of Stuckmann.
Morison should have collected his hat-trick within 28 minutes, as Gregory intercepted the ball inside the box squared it to Morison who somehow put his shot wide with the goal gapping.
The target man had yet another opportunity to grasp his hat-trick after neat play down the left was whipped in by Joe Martin for the unchallenged Morison but headed over.
Millwall could have had several goals in the first half, with another glorious chance as Gregory again put a dangerous low ball across goal for O’Brien this time, but scuffed his shot wide.
In the second half, Doncaster had a chance to claw their way back into the game as Aaron Taylor-Sinclair chased a loose ball out wide and lofted the ball towards the far post for Tyson to head wide.
Morison continued his search for a hat-trick, as Carlos Edwards clipped a ball into box which Morison met but was palmed away by Stuckmann for a corner.
The visitors almost found a fortunate goal, as substitute Harry Forrester’s’ free-kick deflected goalwards but went wide of the target – with Jordan Archer stationary.
Millwall kept Doncaster at bay to collect a deserved clean sheet, as Millwall extend their unbeaten run to five games in all competitions – with Bradford City ahead visiting ‘The Den’ on Saturday.
Millwall Team Lineup: 13 Jordan Archer, 3 Joe Martin, 4 Carlos Edwards, 5 Tony Craig, 9 Lee Gregory (69), 16 Mark Beevers, 18 Shane Ferguson (92), 20 Steve Morison, 21 George Saville, 22 Aiden O’Brien (86), 24 Ben Thompson
Substitutes: 1 David Forde, 2 Shaun Cummings, 10 Fred Onyedinma (69), 11 Lee Martin (86), 17 Byron Webster (92, 23 Jack Powell, 29 Alfie Pavey
Doncaster Rovers Lineup: 12 Thorsten Stuckmann, 2 Mitchell Lund (77), 3 Cedric Evina, 4 Luke McCullough, 6 Andy Butler, 7 Richard Wellens (53), 8 14 Nathan Tyson, 20 Aaron Taylor-Sinclair, James Coppinger ©, 27 Cameron Stewart (56), 29 Harry Middleton
Substitutes: 23 Marko Marosi, 10 Harry Forrester (53), 11 Andy Williams (77), 15 Dany N’Guessan (56), 16 Oscar Gobern, 18 Paul Keegan, 32 Billy Whithouse