OXFORD United were unable to take advantage of rivals dropping points elsewhere as they crashed to defeat at home to Southend United.
Chris Wilder’s side retain a slim chance of claiming a play-off place in the final game of the season next weekend, but a poor first half display prevented them from strengthening their case.
An error from debutant goalkeeper Connor Ripley allowed Ryan Hall’s free-kick to open the scoring and the Shrimpers quickly doubled their lead through Bilel Mohsni.
The U’s were on top for much of the second half but could not find a way back into the game as their winless run was extended to six games.
The United starting line-up showed four changes from the 1-1 draw at Plymouth Argyle a week earlier.
Ripley made his debut in goal after signing from Middlesbrough as an emergency loan following an injury to Wayne Brown in training.
Damian Batt, Simon Heslop and Jon-Paul Pittman also started, as Peter Leven, Adam Chapman and Cristian Montano made way.
The U’s had made a habit of conceding early goals, but they looked the more likely to score in a bright opening.
Dean Morgan saw a shot saved by Southend goalkeeper Cameron Belford’s outstretched leg on six minutes, with Asa Hall firing the rebound over.
Morgan and Pittman combined to set up a chance for Heslop with the next attack, but a deflection took the sting out of the midfielder’s shot.
Both United centre backs, Jake Wright and Michael Duberry, were booked within 60 seconds of each other.
The latter gave Southend a free-kick in a central position 25 yards out. Hall’s 19th-minute effort had power but was straight at Ripley, who somehow let the ball past his hands and into the net.
The error from the teenager was a body blow to the hosts, who lost their fluency in possession and became increasingly direct, with little success.
The task facing the hosts grew even more daunting on 31 minutes, when the Shrimpers doubled their lead.
A looping cross from the left should have been dealt with, but Mohsni leapt highest to expertly glance a header into the far corner.
Ripley was beaten for a third time six minutes before the break, when Neil Harris chipped the ball past the goalkeeper, but Duberry raced back to clear off the line.
United finished the half on top, with Whing drawing a save from Belford and Morgan heading over, but the 2-0 scoreline prompted some boos from the home fans at half-time.
Chapman was brought on at the interval and the midfielder had the first clear chance of the second half, on 56 minutes.
Scott Rendell crossed for Pittman to lay-off, but the substitute could not readjust his feet and shot harmlessly over.
With half an hour to play Tom Craddock was brought on for his first appearance since January.
The impressive Pittman came close to pulling a goal back midway through the second half. Running on to Chapman’s long throw the striker attempted to slot past Belford, who blocked.
Montano was introduced as the final throw of the dice with 15 minutes left.
The West Ham loanee quickly made an impact, jinking into the box before being tripped, but to the U’s amazement the referee gave a goal kick.
The setback proved the final straw for many home fans, who began to file out.
On the pitch United could not exert any late pressure to set up a grandstand finish as Southend held on for victory.
Attendance: 9,356 (1,106 visitors) Oxford Utd: Ripley, Batt, Duberry, Wright, Davis, Heslop (Chapman 46), Whing (Montano 76), Hall, Pittman, Rendell, Morgan (Craddock 58) Substitutes: Crocombe, Capaldi.