KEVIN NUGENT celebrated his first League win in charge of the O's thanks to a heroic performance at the Keepmoat Stadium. With a numbers thin on the ground, Orient worked tirelessly to grab all three points thanks to an early goal from Jay Simpson and a second half wonder strike from Darius Henderson.
The makeshift back four repelled everything that came their way whilst Marvin Bartley put in arguably his finest performance in an O's shirt as he dominated the midfield territory in Yorkshire.
With Romain Vincelot the latest name to be added to the ever-growing injury list with a knee problem, Bartley returned to midfield as Orient moved back to a 4-4-2 with Jobi McAnuff also returning from suspension to take a place on the right.
The defence required a reshuffle following suspensions for Nathan Clarke and Mathieu Baudry as Shane Lowry and Scott Cuthbert took up the centre back positions with Elliot Omozusi returning to left back and Bradley Pritchard filling in at right back
It was the dream start for the O's as they grabbed the lead with their first attack. Jay Simpson who has been in fine scoring form of late, grabbed his fourth of the season when he tussled for possession in the left channel and kept his calm to slot past Jed Steer.
Orient were all over their opponents but it was Rovers who had the next chance five minutes later when James Coppinger looked like he had wriggled past Cuthbert, but the Scotsman and skipper recovered well to block his shot.
Dagnall was next to go close after some woeful defending by Reece Wabara as the home supporters started to get on the backs of their players.
The home side settled though after some shaky defending and looked a threat when Coppinger got on the ball. Simpson looked a class act for the O's as he controlled a number of tough balls and wriggled out of some tight areas early on.
Orient were left thanking their lucky stars on 18 minutes to be remain in front. After a questionable decision to not give a free-kick in favour of Marvin Bartley, Nathan Tyson found space in the left channel and was denied brilliantly by Woods to his left. The rebound fell kindly however for Coppinger who had an open goal from six yards but struck his effort straight against Omozusi.
Bartley clearly felt a sense of injustice but produced a piece of magic to release McAnuff on the right a minute later who whipped in a lethal looking cross that somehow was scrambled behind with Dagnall and Henderson lurking.
Bartley was doing his all to plug the Vincelot-sized gap in the O's midfield and picked out a number of clever passes as Orient had the better of the midfield battle though still looked a tad vulnerable on the counter.
Henderson showed a touch of class to play in Jack Price as the half wore on but the ball just didn't drop kindly for him as he fired wide.
Donny boss Paul Dickov was left feeling enraged with five minutes of the half remaining when Woods misjudged a long ball that bounced over him. Nathan Tyson looked to control and take aim for goal when it was deflected by Cuthbert. Rovers felt it struck his hand but nothing was given.
There was still time for Woods to make a fine save to deny Tyson and McAnuff and Harry Forrester to tussle as both were booked before a breathless half came to an end.
Orient weren't as explosive out of the blocks in the second period as they were the first and will have been disappointed with their ball retention early on as they invited pressure on themselves.
The O's settled though with 10 minutes of the half played and Dagnall would have been disappointed not to work Steer harder from a dangerous Omozusi cross.
The home supporters found their voice and got behind their side but it was Orient who extended their lead in style thanks to the left foot of Henderson. The big man collected an overhit corner on the right, pulled the ball back onto his left foot and curled a shot brilliantly into the top corner from the corner of the box.
Orient were tireless in their work rate, hassling and pressing Rovers at every opportunity as the home side went in search of a way back into it.
Coppinger looked Rovers' best player by a country mile and he put in a stunning ball with 15 minutes to from the right that evaded everyone with Woods beaten.
One concern will be the extent of the injury sustained by Price who was replaced by Lee with 12 minutes remaining after a firm but fair challenge left him in a heap in the centre circle.
Lowry and Cuthbert may have been a makeshift central defensive pairing but they defended their penalty area heroically all evening.
It was backs against the wall at times in the dying stages but Orient held on for a much needed and much deserved victory.
ORIENT: Woods, Omozusi, Cuthbert, (C) Lowry, Pritchard, Simpson, Bartley, Price (Lee 79), McAnuff, Dagnall (Batt 86), Henderson
SUBS: Kashket, Grainger, Ling, Agyemang, Adeboyejo
Goals: Simpson 2, Henderson 62
BOOKED: McAnuff 44, Dagnall 85
DONCASTER: Steer, Furman, McCombe (Robinson 84), Forrester (Bennett 52), McCullough, Tyson, Wellens, De Va (Main 64), Wabara, Wakefield, Coppinger (c)
SUBS: Marosi, Evina, Main, Keegan, Lund
BOOKED: Forrester 44, Wabara 88
Attendance: 5205 (236)
Ref: C Sarginson