Warren Feeney has left Glentoran by mutual consent after nine months in charge of the east Belfast club.
Feeney’s departure follows Saturday’s 3-0 defeat by Loughgall at the Oval, a result that saw the Glens drop to fifth place in the Irish Premiership table.
The 43-year-old was appointed Glens boss in June 2023, succeeding Rodney McAree, who left to become manager of Dungannon Swifts.
Feeney, 46-times capped by Northern Ireland, previously managed Linfield.
Glentoran will meet the Blues in an Irish Cup semi-final at the Oval on 29 March.
Feeney guided his side to the County Antrim Shield final, which they lost 2-1 to Larne in January, but it has been the erratic nature of their league form which will have caused most concern.
The Glens have won 14, drawn eight and lost nine of their top-flight fixtures to sit one point behind fourth-placed Crusaders, but a mammoth 24 points adrift of leaders Larne and 22 in arrears of cross-city rivals Linfield.
Feeney’s team had won just one of their last six league outings, that an 8-2 demolition of bottom club Newry City on 17 February.
Before that, they relinquished two-goal leads to draw 2-2 in consecutive home matches against Cliftonville and Carrick Rangers.
Saturday’s comprehensive loss at the hands of Loughgall was preceded by a midweek goal-less draw at Glenavon.
Among the highlights of Feeney’s nine-month tenure was a 4-0 victory over Linfield at the Oval on 1 December, a result David Healy’s championship-chasing charges avenged to some extent with a 2-0 win at Windsor Park on Boxing Day.
Despite having the significant financial support of Iranian businessman Ali Pour and adopting a full-time model in recent years, the Glens have failed to make any sustained challenge for league title honours and their most recent trophy success was an Irish Cup triumph under former manager Mick McDermott in July 2020.
Pressure grew on Feeney following their defeat on Saturday, a performance which the former Northern Ireland striker himself described as “totally unacceptable”.
Subsequently, a number of Glentoran supporters’ clubs called on owner Pour to make changes at the club.
Feeney had been managing National League South side Welling United when he took charge of the Glens, having previously been at the helm of Ards and Bulgarian side OFC Pirin Blagoevgra.