MK Dons were dealt a huge blow in their bid for Sky Bet League One survival as they were beaten 4-0 by Southend United at Roots Hall.
Theo Robinson scored a hat-trick for the Shrimpers, who also had Stephen McLaughlin get on the scoresheet.
The defeat means the Dons are now six points adrift of safety with three games left to play in the 2017/18 season. They travel to Bradford City on Tuesday night where nothing less than a win will suffice while they will also need other results to go their way to avoid their fate being sealed.
Dean Lewington made his 700th career appearance while Dan Micciche made two changes to his starting XI. Peter Pawlett missed out after picking up a knock in the week and he was replaced by Marcus Tavernier. The other change saw Ousseynou Cisse come in for Scott Golbourne, as the Dons switched to a back four.
Chuks Aneke had the first attempt on goal five minutes in but his right-footed effort from the edge of the area was blocked and then cleared away by a Southend defender.
The Shrimpers then threatened via a cross from Stephen McLaughlin, which Ed Upson turned over the crossbar. The Dons were able to deal with the resulting set piece.
Upson stood over a free-kick on the quarter-hour mark and picked out Aneke with his ball into the area. Aneke teed up Elliott Ward for a shot but referee Gavin Ward stopped play for a foul by the Dons’ number 10.
Soon after, Michael Kightly sent an effort over the crossbar from Jason Demetriou’s cross before Upson and Aneke linked up again from a free-kick - the latter met the ball in but headed over the bar.
There was very little in the way of clear-cut chances until the 23rd minute when Dru Yearwood forced Wieger Sietsma into a diving save. The Dutchman kept the effort out but the loose ball fell to Robinson, who had the simplest of finishes to make it 1-0, despite appeals for offside from the Dons players.
Aneke went close to an instant response with a fierce right-footed effort which was deflected behind by a sliding John White. Sietsma then got down well to keep Stephen McLaughlin’s fizzing drive from finding the bottom right corner of the net.
Southend doubled their lead in the 32nd minute through Robinson, who played a one-two with Michael Timlin on the edge of the box before curling a sublime shot past Sietsma. 2-0.
Looking to get his side back into the game before half time, Aneke raced onto a through ball but, under pressure from White, fired wide. Tavernier also missed the target with an attempt on goal - a left-footed strike following some good play by Cisse.
Tavernier went closer to finding the net on 42 minutes but sent his effort just wide of the left upright.
Sietsma then kept the Dons in it with two strong saves - the first one denied Marc-Antoine Fortune, who was through one-on-one, and the second one saw him tip a long-range shot from McLaughlin over his bar.
Micciche made the first of his three substitutions at the break, replacing Tavernier with Robbie Muirhead.
On 56 minutes, his side almost created an opportunity for Ike Ugbo to reduced the deficit but, after being found by Aneke, Brittain’s low cross towards the Chelsea loanee was intercepted by Anton Ferdinand.
Muirhead also saw a delivery for Ugbo cut out by Ferdinand before the hosts extended their lead further through McLaughlin, who glanced a header into the far corner from Kightly’s free-kick. 3-0.
Southend’s third goal prompted the introduction of Kieran Agard. He was on the pitch for no more than 30 seconds when the hosts went close to scoring a fourth - Kightly’s attempt bending around the far post.
Both Muirhead and Ugbo had shots blocked in quick succession before Ugbo made way for Brandon Thomas-Asante.
With a quarter of an hour left to play, Southend added to their advantage with Robinson completing his hat-trick after the Dons failed to deal with a corner in from the left. 0-4.
Mark Oxley produced a double save in stoppage time to prevent the Dons restoring some pride.
In the end it finished 4-0 - a disappointing day for the Dons who will have to pick themselves up quickly ahead of Tuesday’s must-win match at Bradford City.
Starting XI: Sietsma; Williams, Wootton, Ward, Lewington (c); Upson (Agard 65), Cisse; Brittain, Aneke, Tavernier (Muirhead 46); Ugbo (Thomas-Asante 75).
Unused subs: Jones (GK), Golbourne, Ebanks-Landell, Reo-Coker.
Booked: Tavernier, Aneke, Ward
Referee: G Ward
Attendance: 7,546 (390 away)