The Robins lost goalkeeper Tyrell Belford who was sent off for a professional foul in the 20th minute only to be replaced by his brother Cameron and his first touch was to save Lloyd James’s penalty.
Dean Cox gave his side the lead following a defensive lapse and Orient doubled their lead at the start of the second half but Anton Rodgers reduced the deficit and Andy Williams’s 86th minute penalty levelled the
Orient were relegated as a results of scores elsewhere in League One while Swindon now face Sheffield United in the League One Play Offs.
Mark Cooper made nine changes for the visit of Leyton Orient who needed a win to have any chance of avoiding relegation and the match started in bright sunshine with the visitors kicking off towards the Town End. Orient had a corner in the 2nd minute when Ricketts headed a cross behind and when the ball was crossed, Jay Simpson had weak claims for a penalty after he tumbled under a defensive challenge but the referee Dean Whitestone waved his appeals.
The visitors continued to push forward in numbers probing for an opening and Lloyd James tried his luck from 20 yards but his shot went high and wide.
Town’s first corner of the match in the 15th minute saw Williams collect the ball after Swift had dribbled his way into the penalty area but the visiting keeper Cisak pushed his shot away.
Josh Wright then collected the ball in midfield and ran unchallenged before unleashing a scuffed shot from 12 yards but his effort went wide.
Disaster struck in the 19th minute when a weak defensive clearance only reached an Orient player who sent a first time pass towards the penalty area where Tyrell Belford brought down Lloyd James in the penalty area and the referee immediately awarded a penalty after showing a red card to Belford. Joshua Cooke was substituted in order for Cameron Belford to take over in goal and he made an immediate
impact saving James penalty diving to his left to push the ball away for it to be cleared by the defence.
Orient earned a corner in the 25th minute when Ricketts deflected a cross behind but the Town defence cleared the danger.
There was a break in play as the match entered the 27th minute for Will Randall to receive treatment after making a challenge in Town’s penalty area but he was able to continue after treatment.
Raphael Rossi-Branco made a superb clearance in the 31st minute under pressure just as Dean Cox was poised to shoot and the Orient player needed treatment after colliding with the Town defender although he was able to rejoin play.
John Swift then decided to try and inject some creativity in midfield taking on a number of Orient players before losing possession in the 33rd minute but Town continued to push forward and a late offside flag then denied the Robins a shot on goal.
Dean Cox tried his luck in the 36th minute with a flicked effort after the ball had been crossed to the far post but his effort went wide.
Orient had a corner conceded by Rossi-Branco in the 38th minute which led to Nathan Clarke heading well over and shortly afterwards Chris Dagnall blazed over from the edge of the area.
Disaster struck again for Town in the 40th minute when poor control by Rossi-Branco saw him dispossessed by the lively Dean Cox who advanced several paces before firing to the right of Cameron Belford to give his side a 40th minute lead.
The 4th official indicated that 6 minutes of additional time would be played and Town’s best effort saw Swift try his luck from 25 yards with an angled shot but the keeper parried the ball and grabbed it at the second attempt.
The half time whistle was blown with torrential rain falling with ten-men Town behind by one goal.
Jack Stephens replaced Jordan Turnbull at half time but Town’s defensive frailties were exposed in the 47th minute when the defence failed to clear the ball despite having three opportunities before Chris Dagnall scored with a first time shot past Belford. Town were still trying to get some shape before Cox almost scored again with an angled shot but the ball hit the crossbar and rebounded onto the line before being cleared.
Andy Williams tried his luck with an angled shot from 20 yards but his effort went wide and Orient responded with another crisp shot from Josh Wright but that trickled just wide of the goal.
Shane Lowry replaced Elliot Omozusi in the 55th minute with the visitors looking to build on their lead.
Swindon were struggling to get anywhere near the Orient goal but eventually they were awarded a free kick when Swift was bodychecked on the edge of the area in the 60th minute which led to a peach of a goal when a short kick routine saw Swift pass the ball to Anton Rodgers who sent a superb volley past the despairing dive of Alex Cisak.
Harry Agombar was replaced by Lee Marshall during the break in play before the match was restarted.
Town fans were incensed midway through the half when a late challenge on Barthram in the centre circle went unpunished and the visitors went on to earn a corner which was held up while Barthram received treatment.
Andy Williams went close to equalising after tricking his way into the penalty area before firing just wide of goal and the Town player was then cautioned for protesting that the referee should have awarded a corner.
Will Randall went close for Town in the 72nd minute with an audacious lobbed effort which beat the keeper but the ball went over the bar.
Orient replaced Simpson with Jobi Mcanuff in the 74th minute.
A superb move started by Rodgers saw him spray the ball out to the right wing where it was picked up by Barthram who sent a superb cross to the back post where it reached Swift but the ball ricocheted off him and over the bar.
Williams continued to try and get Town level and he tried his luck with another shot from the angle of the penalty area but the ball went over the bar.
Jack Stephens again showed his defensive strength outmuscling Dagnall in front of goal before clearing under pressure in the 79th minute.
Former Town player Scott Cuthbert replaced Cox in the 81st minute.
Swindon were awarded a penalty in the 86th minute when Sam Ricketts was tripped near the goalline while chasing down a loose ball and up stepped Andy Williams to fire powerful penalty past Cisak to level the scores for his 22nd goal of the season.
Orient went all out on the attack to try and get back in the lead but frayed tempers on both sides led to a break in play after the referee waved away penalty claims for the visitors shortly after ignoring claims for a foul on Will Randall in the Orient half.
The visitors had a corner deep in the five minutes of added time which saw their keeper attempt to get a shot on goal but he played an air shot and missed, allowing the Town defence to clear.
The final whistle was blown to end Town’s normal League season and as a result of scores elsewhere, Leyton Orient are relegated along with Yeovil, Crawley and Notts County.
Swindon Town now face Sheffield United in the two-legged Play Off Semi Finals starting with the first leg on Thursday May 7th at Bramall Lane.