Rangers failed to ease the pressure on beleaguered boss Russell Martin after Celtic held them to a dour 0-0 draw in Sunday's Old Firm derby.
Martin is battling to avoid the sack just 11 games into his Ibrox reign and Rangers' latest lacklustre performance did little to strengthen his tenuous position.
Just days after a humiliating Champions League play-off round exit against Club Brugge, who won 6-0 to complete a 9-1 aggregate victory, Martin endured more boos at the final whistle after an unusually tepid showdown with Celtic.
Rangers are languishing in sixth place in the Scottish Premiership after drawing their first four league games.
They already trail leaders Celtic by six points in a dismal start to their bid to end their arch rivals' four-year reign as Scottish champions.
Rangers have won only three times in all competitions since Martin arrived in Glasgow in the close-season.
His appointment was not greeted with enthusiasm by Rangers fans after he was sacked by Southampton last term during a campaign that featured accusations of tactical naivety and ended in relegation from the Premier League after his exit.
Rangers chairman Andrew Cavanagh and representatives of the club's new US-based owners 49ers Enterprises, including vice-chairman Paraag Marathe, were in the directors' box to pass judgement on Martin's latest flop.
Martin, 39, heads into the international break hoping he is still in charge when Rangers return to action against Hearts on September 13.
While Celtic's point took them above Hearts to the top of the table, it was hardly a restorative display from Brendan Rodgers' men after their own Champions League woes.
Celtic were beaten on penalties by Kairat Almaty in the play-off round amid fan frustration at the club's quiet transfer window.
Rodgers has also questioned Celtic's failure to improve a squad that strolled to the title and advanced from the Champions League group phase last season.
Rodgers' men finished 17 points clear of Rangers in 2024-25, but the Hoops have now failed to win their last four encounters with their Glasgow foes dating back to last term.
In a game of few chances, Rangers defender John Souttar had the ball in the net in the 32nd minute, only to see his header ruled offside after a VAR check.
